An attorney linked to a former Trump campaign official admitted Tuesday he lied to federal investigators working for special counsel Robert Mueller.

Alex van der Zwaan, who worked at the law firm Skadden, Arps, Slate, Meagher & Flom until he was fired last year, appeared at the federal courthouse in Washington where he formally pleaded guilty to a single charge of making false statements about his interactions with former Trump campaign aide Rick Gates.

Associated Press reporter Eric Tucker says Mueller is sending a clear message that he won't tolerate lying. This is the 4th person to be prosecuted for lying to investigators.

Van der Zwaan's plea comes on the heels of an extraordinary indictment from Mueller last week that charged 13 Russian individuals and three Russian companies in a hidden social media effort to meddle in the 2016 U.S. presidential election by denigrating Democrat Hillary Clinton and boosting the chances of Trump.

But the charge against the attorney, who is also the son-in-law of a Russian billionaire, does not involve election meddling or relate to the Trump campaign's operations. Instead, it stems from the special counsel's investigation into Paul Manafort, Trump's former campaign chair, and Gates, who is a longtime business associate of Manafort.

Gates and Manafort were indicted last year and accused of conspiring to launder millions of dollars they earned from political consulting work in Ukraine. As part of that indictment, Manafort and Gates are accused of directing a covert Washington lobbying campaign on behalf of pro-Russian Ukrainian interests before they joined the Trump campaign. Both have pleaded not guilty.

Van der Zwaan, 33, of London admitted to lying to federal authorities while they questioned him about the production of a report that Manafort and Gates are accused of secretly funding by funneling money through an offshore account.

Washington - 20 February 2018

1. STILL Alex van der Zwaan arriving at the courthouse

2. SOUNDBITE (English) Eric Tucker, Associated Press Justice Department Reporter:

"Today we had another guilty plea in special counsel Robert Mueller's investigation. This is a lawyer. His name is Alex van der Zwaan. He admitted to lying to federal investigators during an interview in November 2017."

3. STILL Alex van der Zwaan arriving at the courthouse

4. SOUNDBITE (English) Eric Tucker, Associated Press Justice Department Reporter:

"This is the 19th person that we've seen charged so far in Mueller's investigation. This is a person who lied to the FBI about his interactions with Rick Gates, who is a codefendant of Paul Manafort, who is the former campaign chairman of President Donald Trump."

5. STILL Alex van der Zwaan arriving at the courthouse

6. SOUNDBITE (English) Eric Tucker, Associated Press Justice Department Reporter:

"He went into the special counsel's office back in November 2017 to be interviewed about his interactions with Rick Gates in connection with the production of a report that related to foreign lobbying work, Ukrainian lobbying work, that Rick Gates and Paul Manafort were doing. And during the course of that conversation he was asked about the last interaction he had with Rick Gates. He lied in that interview according to Mueller's investigators."

7. Mid, van der Zwaan exiting the courthouse and getting into a car

8. SOUNDBITE (English) Eric Tucker, Associated Press Justice Department Reporter:

"So one thing that's really interesting is when you think about the timing of this investigation, this comes right on the heels of a stunning indictment that we had last Friday against 13 Russians and 3 Russian companies in connection to a hidden but very powerful social media effort that Mueller says was aimed at denigrating Hillary Clinton during the 2016 presidential election and aiding the campaign of her Republican opponent Donald Trump."

9. Mid, car driving away

10. SOUNDBITE (English) Eric Tucker, Associated Press Justice Department Reporter:

"The plea today does not relate to the indictment from Friday about the meddling in the 2016 presidential election. And it doesn't directly connect in any way to President Trump or Candidate Trump."

11. STILL van der Zwaan leaving the courthouse

12. SOUNDBITE (English) Eric Tucker, Associated Press Justice Department Reporter:

"But I would say what's really interesting now is this is the fourth person who we have seen charged with lying to investigators. So clearly Mueller is saying if you lie to us, and if we catch you in a lie making a knowing and false and willfully false statement, not just a mistake but a willfully false statement, you could wind up being prosecuted."

13. STILL van der Zwaan leaving the courthouse

14. SOUNDBITE (English) Eric Tucker, Associated Press Justice Department Reporter:

"Alex van der Zwaan is going to be sentenced in April. He was free today, he was allowed to go, allowed to leave the courtroom."

15. STILL van der Zwaan leaving the courthouse

16.SOUNDBITE (English) Eric Tucker, Associated Press Justice Department Reporter:

"That charge that he is pleading guilty to, a charge of making false statements to investigators, technically carries a five year maximum prison sentence. However, under the sentencing guideline ranges that were discussed in court today he's looking at between zero months and six months in prison."

++EDIT ENDS IN A SOUNDBITE++

Thirteen Russians and three Russian entities were charged Friday with an elaborate plot to interfere in the 2016 U.S. presidential election, federal prosecutors announced Friday.

The indictment, brought by the office of special counsel Robert Mueller, alleges that Russians used bogus social media postings and advertisements fraudulently purchased in the name of Americans to sway political opinion during the race between Republican Donald Trump and Hillary Clinton, his Democratic opponent.

The charges are the most direct allegation to date of illegal Russian meddling in the election.

The goal, the indictment says, was to "sow discord in the U.S. political system, including the 2016 presidential election."

Charges include conspiracy, wire fraud, bank fraud and aggravated identity theft.

The charges arise from Mueller's investigation into Russian interference in the election and whether there was improper coordination between the Trump campaign and the Kremlin.

Before Friday, four people, including Trump's former national security adviser and former campaign chairman, had been charged in Mueller's investigation.

The White House had no immediate response to the indictment.

Washington DC - 16 February 2018

1. Wide, Rosenstein walking into news conference

2. SOUNDBITE (English) Rod Rosenstein, Deputy Attorney General:

"A grand jury in the District of Columbia today returned an indictment presented by the special counsel's office. The indictment charges 13 Russian nationals and three Russian companies for committing federal crimes while seeking to interfere in the United States political system including the 2016 presidential election. The defendants allegedly conducted what they called information warfare against the United States with the stated goal of spreading distrust toward the candidates and the political system in general. According to the allegations in the indictment 12 of the individual defendants worked at various times for a company called Internet Research Agency LLC, a Russian company based in St. Petersburg. The other individual defendant Yevgeny Viktorovich Prigozhin funded the conspiracy through companies known as Concord Management and Consulting LLC, Concord catering and many affiliates and subsidiaries.

3. Cutaway reporters

4. SOUNDBITE (English) Rod Rosenstein, Deputy Attorney General:

"Two of the defendants allegedly traveled to the United States in 2014 to collect intelligence for their American influence operations. In order to hide the Russian origins of their activities, the defendants allegedly purchased space on computer servers located here in the United States in order to set up a virtual private network. The defendants allegedly use that infrastructure to establish hundreds of accounts on social media networks such as Facebook, Instagram and Twitter, making it appear that those accounts were controlled by persons located in the United States."

5. Wide, Rosenstein speaking

6. SOUNDBITE (English) Rod Rosenstein, Deputy Attorney General:

"The indictment includes eight criminal counts. Count one alleges a criminal conspiracy to defraud the United States by all of the defendants. The defendants allegedly conspired to defraud America by impairing the lawful functions of the Federal Election Commission, the United States Department of Justice and the Department of State. Those organizations of the U.S. government are responsible for administering federal requirements for disclosure of foreign involvement in certain domestic activities. Count two charges conspiracy to commit wire fraud and bank fraud by Internet Research Agency and two of the individual defendants. Counts three through eight charge aggravated identity theft by Internet Research Agency and four individuals. Now there is no allegation in this indictment that any American was a knowing participant in this illegal activity. There is no allegation in the indictment that the charge conduct altered the outcome of the 2016 election. I want to caution you that everyone charged with a crime is presumed innocent unless and until proven guilty in court. At trial prosecutors must introduce credible evidence that is sufficient to prove each defendant guilty beyond any reasonable doubt to a unanimous jury. Special Counsel's investigation is ongoing. There will be no comments from the special counsel at this time. "

7. Cutaway

8. SOUNDBITE (English) Rod Rosenstein, Deputy Attorney General

"This indictment serves as a reminder that people are not always who they appear to be on the Internet. The indictment alleges that the Russian conspirators want to promote discord in the United States and undermine public confidence in democracy. We must not allow them to succeed. The Department of Justice will continue to work cooperatively with other law enforcement and intelligence agencies and with the Congress to defend our nation against similar current and future efforts."

9. Mid, Rosenstein walking out

Thirteen Russians and three Russian entities were charged Friday with an elaborate plot to interfere in the 2016 U.S. presidential election, federal prosecutors announced Friday.

The indictment, brought by the office of special counsel Robert Mueller, alleges that Russians used bogus social media postings and advertisements fraudulently purchased in the name of Americans to sway political opinion during the race between Republican Donald Trump and Hillary Clinton, his Democratic opponent.

The charges are the most direct allegation to date of illegal Russian meddling in the election.

The goal, the indictment says, was to "sow discord in the U.S. political system, including the 2016 presidential election."

Charges include conspiracy, wire fraud, bank fraud and aggravated identity theft.

The charges arise from Mueller's investigation into Russian interference in the election and whether there was improper coordination between the Trump campaign and the Kremlin.

Before Friday, four people, including Trump's former national security adviser and former campaign chairman, had been charged in Mueller's investigation.

The White House had no immediate response to the indictment.

Washington - 16 February 2018

1. Wide, Rosenstein walking into news conference

2. SOUNDBITE (English) Rod Rosenstein, Deputy Attorney General:

"A grand jury in the District of Columbia today returned an indictment presented by the special counsel's office. The indictment charges 13 Russian nationals and three Russian companies for committing federal crimes while seeking to interfere in the United States political system including the 2016 presidential election. The defendants allegedly conducted what they called information warfare against the United States with the stated goal of spreading distrust toward the candidates and the political system in general. According to the allegations in the indictment 12 of the individual defendants worked at various times for a company called Internet Research Agency LLC, a Russian company based in St. Petersburg. The other individual defendant Yevgeny Viktorovich Prigozhin funded the conspiracy through companies known as Concord Management and Consulting LLC, Concord catering and many affiliates and subsidiaries.

3. Cutaway reporters

4. SOUNDBITE (English) Rod Rosenstein, Deputy Attorney General:

"Two of the defendants allegedly traveled to the United States in 2014 to collect intelligence for their American influence operations. In order to hide the Russian origins of their activities, the defendants allegedly purchased space on computer servers located here in the United States in order to set up a virtual private network. The defendants allegedly use that infrastructure to establish hundreds of accounts on social media networks such as Facebook, Instagram and Twitter, making it appear that those accounts were controlled by persons located in the United States."

5. Wide, Rosenstein speaking

6. SOUNDBITE (English) Rod Rosenstein, Deputy Attorney General:

"The indictment includes eight criminal counts. Count one alleges a criminal conspiracy to defraud the United States by all of the defendants. The defendants allegedly conspired to defraud America by impairing the lawful functions of the Federal Election Commission, the United States Department of Justice and the Department of State. Those organizations of the U.S. government are responsible for administering federal requirements for disclosure of foreign involvement in certain domestic activities. Count two charges conspiracy to commit wire fraud and bank fraud by Internet Research Agency and two of the individual defendants. Counts three through eight charge aggravated identity theft by Internet Research Agency and four individuals. Now there is no allegation in this indictment that any American was a knowing participant in this illegal activity. There is no allegation in the indictment that the charge conduct altered the outcome of the 2016 election. I want to caution you that everyone charged with a crime is presumed innocent unless and until proven guilty in court. At trial prosecutors must introduce credible evidence that is sufficient to prove each defendant guilty beyond any reasonable doubt to a unanimous jury. Special Counsel's investigation is ongoing. There will be no comments from the special counsel at this time. "

7. Cutaway

8. SOUNDBITE (English) Rod Rosenstein, Deputy Attorney General

"This indictment serves as a reminder that people are not always who they appear to be on the Internet. The indictment alleges that the Russian conspirators want to promote discord in the United States and undermine public confidence in democracy. We must not allow them to succeed. The Department of Justice will continue to work cooperatively with other law enforcement and intelligence agencies and with the Congress to defend our nation against similar current and future efforts."

9. Mid, Rosenstein walking out

An attorney linked to a former Trump campaign official admitted Tuesday he lied to federal investigators working for special counsel Robert Mueller.

Alex van der Zwaan, who worked at the law firm Skadden, Arps, Slate, Meagher & Flom until he was fired last year, appeared at the federal courthouse in Washington where he formally pleaded guilty to a single charge of making false statements about his interactions with former Trump campaign aide Rick Gates.

Associated Press reporter Eric Tucker says Mueller is sending a clear message that he won't tolerate lying. This is the 4th person to be prosecuted for lying to investigators.

Van der Zwaan's plea comes on the heels of an extraordinary indictment from Mueller last week that charged 13 Russian individuals and three Russian companies in a hidden social media effort to meddle in the 2016 U.S. presidential election by denigrating Democrat Hillary Clinton and boosting the chances of Trump.

But the charge against the attorney, who is also the son-in-law of a Russian billionaire, does not involve election meddling or relate to the Trump campaign's operations. Instead, it stems from the special counsel's investigation into Paul Manafort, Trump's former campaign chair, and Gates, who is a longtime business associate of Manafort.

Gates and Manafort were indicted last year and accused of conspiring to launder millions of dollars they earned from political consulting work in Ukraine. As part of that indictment, Manafort and Gates are accused of directing a covert Washington lobbying campaign on behalf of pro-Russian Ukrainian interests before they joined the Trump campaign. Both have pleaded not guilty.

Van der Zwaan, 33, of London admitted to lying to federal authorities while they questioned him about the production of a report that Manafort and Gates are accused of secretly funding by funneling money through an offshore account.

Washington - 20 February 2018

1. STILL Alex van der Zwaan arriving at the courthouse

2. SOUNDBITE (English) Eric Tucker, Associated Press Justice Department Reporter:

"Today we had another guilty plea in special counsel Robert Mueller's investigation. This is a lawyer. His name is Alex van der Zwaan. He admitted to lying to federal investigators during an interview in November 2017."

3. STILL Alex van der Zwaan arriving at the courthouse

4. SOUNDBITE (English) Eric Tucker, Associated Press Justice Department Reporter:

"This is the 19th person that we've seen charged so far in Mueller's investigation. This is a person who lied to the FBI about his interactions with Rick Gates, who is a codefendant of Paul Manafort, who is the former campaign chairman of President Donald Trump."

5. STILL Alex van der Zwaan arriving at the courthouse

6. SOUNDBITE (English) Eric Tucker, Associated Press Justice Department Reporter:

"He went into the special counsel's office back in November 2017 to be interviewed about his interactions with Rick Gates in connection with the production of a report that related to foreign lobbying work, Ukrainian lobbying work, that Rick Gates and Paul Manafort were doing. And during the course of that conversation he was asked about the last interaction he had with Rick Gates. He lied in that interview according to Mueller's investigators."

7. Mid, van der Zwaan exiting the courthouse and getting into a car

8. SOUNDBITE (English) Eric Tucker, Associated Press Justice Department Reporter:

"So one thing that's really interesting is when you think about the timing of this investigation, this comes right on the heels of a stunning indictment that we had last Friday against 13 Russians and 3 Russian companies in connection to a hidden but very powerful social media effort that Mueller says was aimed at denigrating Hillary Clinton during the 2016 presidential election and aiding the campaign of her Republican opponent Donald Trump."

9. Mid, car driving away

10. SOUNDBITE (English) Eric Tucker, Associated Press Justice Department Reporter:

"The plea today does not relate to the indictment from Friday about the meddling in the 2016 presidential election. And it doesn't directly connect in any way to President Trump or Candidate Trump."

11. STILL van der Zwaan leaving the courthouse

12. SOUNDBITE (English) Eric Tucker, Associated Press Justice Department Reporter:

"But I would say what's really interesting now is this is the fourth person who we have seen charged with lying to investigators. So clearly Mueller is saying if you lie to us, and if we catch you in a lie making a knowing and false and willfully false statement, not just a mistake but a willfully false statement, you could wind up being prosecuted."

13. STILL van der Zwaan leaving the courthouse

14. SOUNDBITE (English) Eric Tucker, Associated Press Justice Department Reporter:

"Alex van der Zwaan is going to be sentenced in April. He was free today, he was allowed to go, allowed to leave the courtroom."

15. STILL van der Zwaan leaving the courthouse

16.SOUNDBITE (English) Eric Tucker, Associated Press Justice Department Reporter:

"That charge that he is pleading guilty to, a charge of making false statements to investigators, technically carries a five year maximum prison sentence. However, under the sentencing guideline ranges that were discussed in court today he's looking at between zero months and six months in prison."

++EDIT ENDS IN A SOUNDBITE++

The list of Russians indicted over of an elaborate plot to disrupt the 2016 US presidential election "does not look like the result of a solid investigation," a Russian investigative journalist said on Saturday

Andrey Zakharov and his colleague Polina Rusyaeva published an October 2017 investigation into the work of Russian Kremlin trolls factory before, during and after the US election.

Zakharov said the list which included the alleged "troll factory" owner Yevgeny Prigozhin, looked "quite random."

Prigozhin is a wealthy St. Petersburg businessman with ties to the Russian government and President Vladimir Putin.

In an extraordinary indictment, the US special counsel has accused 13 Russians of an elaborate plot to disrupt the 2016 presidential election, charging them with running a huge but hidden social media trolling campaign aimed in part at helping Republican Donald Trump defeat Democrat Hillary Clinton.

The federal indictment, brought Friday by special counsel Robert Mueller, represents the most detailed allegations to date of illegal Russian meddling during the campaign that sent Trump to the White House.

It also marks the first criminal charges against Russians believed to have secretly worked to influence the outcome.

Moscow - 17 February 2018

1. Various set-up shots with RBC investigative journalist Andrey Zakharov

2. SOUNDBITE (Russian) Andrey Zakharov, RBC investigative journalist:

"In general, in my opinion, the list looks quite random. They simply included in it all the names they could find. According to our information part of these people don't work at the factory now and did not even work there during the (US) elections. So this list reminds us of another Kremlin list submitted to Congress earlier, which is pretty much the whole of Forbes list, copy and pasted list of top Kremlin officials, heads of state companies from RBC magazine rating. So they included everyone they knew about. This does not look like the result of a solid investigation."

3. Various of Zakharov looking through report on Kremlin trolls on RBC website

4. SOUNDBITE (Russian) Andrey Zakharov, RBC investigative journalist:

"In regards to the (Trolls) factory there isn't even any indirect evidence (meaning legal proof of Russian entrepreneur Yevgeny Prigozhin's links to the Internet Research Agency) There are some document leaks published by Anonymous International group and many testimonies by former factory workers who say it's a "common knowledge" that this structure is owned by Prigozhin. They have a lot of legal entities, including IRA (Internet Research Agency) which are known about in the States, but in fact this legal entity has not existed for over a year."

5. Various of Zakharov looking through phone

6. SOUNDBITE (Russian) Andrey Zakharov, RBC investigative journalist:

"(Prigozhin takes care of) the state market for food provision for schools and army, and structures linked to him became large catering services providers for (Russian) Defence Ministry military units. Apart from this, he is believed to be sponsoring the Wagner private military company, whose members fought in east Ukraine and then in Syria, where as we know, they recently suffered a heavy defeat."

7. Various exteriors of RBC building

In an extraordinary indictment, the U.S. special counsel accused 13 Russians Friday of an elaborate plot to disrupt the 2016 presidential election, charging them with running a huge but hidden social media trolling campaign aimed in part at helping Republican Donald Trump defeat Democrat Hillary Clinton.

The federal indictment, brought by special counsel Robert Mueller, represents the most detailed allegations to date of illegal Russian meddling during the campaign that sent Trump to the White House. It also marks the first criminal charges against Russians believed to have secretly worked to influence the outcome.

The latest indictment does not focus on hacking but instead centers on a social media propaganda effort that began in 2014 and continued past the election, with the goal of producing distrust in the American political process.

The indictment does not allege that any American knowingly participated in Russian meddling, or suggest that Trump campaign associates had more than "unwitting" contact with some of the defendants who posed as Americans during election season.

But it does lay out a vast and wide-ranging Russian effort to sway political opinion in the United States through a strategy that involved creating Internet postings in the names of Americans whose identities had been stolen; staging political rallies while posing as American political activists and paying people in the U.S. to promote or disparage candidates.

"This involved having agents sometimes come to the U.S. from Russia and start all sorts of interest groups on Facebook and other social media and then to entice people, not only into joining those groups, but also to have them post a great deal of material on the social networks, a lot of it aimed at criticizing Hillary Clinton and rivals to Donald Trump during the Republican primaries," said AP technology editor David Hamilton.  

While foreign meddling in U.S. campaigns is not new, the indictment for an effort of this scope and digital sophistication is unprecedented.

The surreptitious campaign was organized by the Internet Research Agency, a notorious Russian troll farm that the indictment says sought to conduct "information warfare against the United States of America."

The election-meddling organization, looking to conceal its Russian roots, purchased space on computer servers within the U.S., used email accounts from U.S. internet service providers and created and controlled social media pages with huge numbers of followers on divisive issues such as immigration, religion and the Black Lives Matter movement.

Starting in April 2016, the indictment says, the Russian agency bought political ads on social media supporting Trump and opposing Clinton without reporting expenditures to the Federal Election Commission or registering as foreign agents. Among the ads: "JOIN our #HillaryClintonForPrison2016" and "Donald wants to defeat terrorism ... Hillary wants to sponsor it."

The indictment also asserts that the posts encouraged minority groups not to vote or to vote for third parties and alleged Democratic voter fraud.

Facebook says it is doubling its security staff to 20,000 and actively working with the FBI to stop election interference by Russians and others.

Washington, D.C. - 16 February 2018

1. SOUNDBITE (English) Rod Rosenstein, Deputy Attorney General:

"A grand jury in the District of Columbia today returned an indictment presented by the special counsel's office. The indictment charges 13 Russian nationals and three Russian companies for committing federal crimes while seeking to interfere in the United States political system."

2. Various views of the U.S. Department of Justice statement regarding the Russia indictment

San Francisco - 16 February 2018

3. SOUNDBITE (English) David Hamilton, AP Technology Editor:

"It basically lays out a strategy by a Russian organization called the internet research agency to interfere with the 2016 presidential election. This involved having agents sometimes come to the U.S. from Russia and start all sorts of interest groups on Facebook and other social media and then to entice people, not only into joining those groups, but also to have them post a great deal of material on the social networks, a lot of it aimed at criticizing Hillary Clinton and rivals to Donald Trump during the Republican primaries while also supporting Bernie Sanders and Donald Trump himself."

Washington, D.C. - 16 February 2018

4. Still image of Facebook posting released by the House Intelligence Committee

San Francisco - 16 February 2018

5. SOUNDBITE (English) David Hamilton, AP Technology Editor:

"It's been a rough year for Facebook and Twitter and YouTube and the like. They all got hauled up in front of congressional committees back in November and quizzed extensively about this. They say they've taken a number of actions including hiring more people to vet the sort of material that's published on their networks and to try to screen out false and misleading accounts. But experts have a lot of doubts as to whether they've actually gone far enough in terms of being able to deal with this and to be ready, for instance, for the 2018 midterms."

6. SOUNDBITE (English) David Hamilton, AP Technology Editor:

"As far as what can be done, I think that's the biggest question everybody's trying to wrestle with right now, the companies, the government, users of the social media organizations themselves."

Facebook CEO Mark Zuckerberg disclosed Tuesday his company is "working with" special counsel Robert Mueller in the federal probe of Russian interference in the 2016 presidential campaign - and working hard to change its own operations after the harvesting of users' private information by a Trump campaign-affiliated data-mining company.

The founder of the social media giant publicly apologised for his company's errors in failing to better protect the personal information of its millions of users, a controversy that has brought a flood of bad publicity and sent the company's  stock value plunging.

He seemed to achieve a measure of success: Facebook shares surged 4.5 percent for the day, the biggest gain in two years.

Zuckerberg told the Senate Judiciary and Commerce committees that he has not been personally interviewed by Mueller's team, but "I know we're working with them."

He offered no details, citing a concern about confidentiality rules of the investigation.

Earlier this year Mueller charged 13 Russian individuals and three Russian companies in a plot to interfere in the 2016 presidential election through a social media propaganda effort that included online ad purchases using US aliases and politicking on US soil. A number of the Russian ads were on Facebook.

During Tuesday's at-times-contentious hearing, Zuckerberg said it had been "clearly a mistake" to believe the data-mining company Cambridge Analytica had deleted user data that it had harvested in an attempt to sway elections. He said Facebook had considered the data collection "a closed case" because it thought the information had been discarded.

Facebook also didn't alert the Federal Trade Commission, Zuckerberg said, and he assured senators the company would handle the situation differently today.

He began a two-day congressional inquisition with a public apology for the way Facebook handled the data-mining of its users' data. He took responsibility for failing to prevent Cambridge Analytica, which was affiliated with Donald Trump's presidential campaign, from gathering personal information from 87 million users.

"I think he went a long ways toward giving the kind of assurance that Facebook certainly wants to come out of this kind of hearing. I don't think he was nicked too badly," said David Levine, a professor at the University of California Hastings College of the Law.

Separately, the company began alerting some of its users that their data was gathered by Cambridge Analytica. A notification that appeared on Facebook for some users Tuesday told them that "one of your friends" used Facebook to log into a now-banned personality quiz app called "This Is Your Digital Life." The notice says the app misused the information, including public profiles, page likes, birthdays and current cities, by sharing it with Cambridge Analytica.

Berkeley, California – 10 April 2018

1. David Levine, law professor at University of California Hastings College of the Law, watching Facebook CEO Mark Zuckerberg testimony in living room at home

2. Levine sitting in chair, watching testimony

3. TV screen showing Zuckerberg testimony

4. SOUNDBITE (English) David Levine, law professor, University of California Hastings College of the Law:

"Mark Zuckerberg had a tall order today. He really had a lot to get done, which is he had to assure members of the Senate that Facebook was on top of the problem, that they had apologised, that they understood the scope of the problems, and that Facebook was taking significant measures to correct those problems. Mr. Zuckerberg also needed to reassure the billions of users around the world that the safety and security of users' data is paramount in the minds of the top officials at Facebook and that they want to make sure that it's as protected as possible."

5. Levine watching Zuckerberg testimony in living room

6. SOUNDBITE (English) David Levine, law professor, University of California Hastings College of the Law:

"He was very good at looking sincere the way he needs to, looking contrite, making eye contact when he needed to, looking down when he needed to look a little 'I'm hearing you' that sort of thing, so he certainly looked coached. He looked sincere. He looked like he wanted to work with the senators. But he also held his position. If there were issues about will you support a certain type of legislation, where obviously Facebook doesn't really want to support it, he said 'well I agree with the general principle and certainly our team can work with your people,' but when they tried to corner him about 'will you support certain legislation' he wouldn't do it."

7. Zuckerberg and hearing on television

8. SOUNDBITE (English) David Levine, law professor, University of California Hastings College of the Law:

"I think he went a long ways toward giving the kind of assurance that Facebook certainly wants to come out of this kind of hearing. I don't think he was nicked too badly. I think there were a couple questions around Cambridge Analytica where he sounded more ignorant, didn't have facts on his fingertips in the way that maybe he should have. But by and large I think at Facebook headquarters they're going to say, certainly at the end of today, there are still more hearings, but - mission accomplished."

9. Levine watching Zuckerberg testimony in living room

Facebook CEO Mark Zuckerberg disclosed Tuesday his company is "working with" special counsel Robert Mueller in the federal probe of Russian interference in the 2016 presidential campaign - and working hard to change its own operations after the harvesting of users' private information by a Trump campaign-affiliated data-mining company.

The founder of the social media giant publicly apologized for his company's errors in failing to better protect the personal information of its millions of users, a controversy that has brought a flood of bad publicity and sent the company's  stock value plunging. He seemed to achieve a measure of success: Facebook shares surged 4.5 percent for the day, the biggest gain in two years.

Zuckerberg told the Senate Judiciary and Commerce committees that he has not been personally interviewed by Mueller's team, but "I know we're working with them." He offered no details, citing a concern about confidentiality rules of the investigation.

Earlier this year Mueller charged 13 Russian individuals and three Russian companies in a plot to interfere in the 2016 presidential election through a social media propaganda effort that included online ad purchases using U.S. aliases and politicking on U.S. soil. A number of the Russian ads were on Facebook.

During Tuesday's at-times-contentious hearing, Zuckerberg said it had been "clearly a mistake" to believe the data-mining company Cambridge Analytica had deleted user data that it had harvested in an attempt to sway elections. He said Facebook had considered the data collection "a closed case" because it thought the information had been discarded.

Facebook also didn't alert the Federal Trade Commission, Zuckerberg said, and he assured senators the company would handle the situation differently today.

He began a two-day congressional inquisition with a public apology for the way Facebook handled the data-mining of its users' data. He took responsibility for failing to prevent Cambridge Analytica, which was affiliated with Donald Trump's presidential campaign, from gathering personal information from 87 million users.

"I think he went a long ways toward giving the kind of assurance that Facebook certainly wants to come out of this kind of hearing. I don't think he was nicked too badly," said David Levine, a professor at the University of California Hastings College of the Law.

Separately, the company began alerting some of its users that their data was gathered by Cambridge Analytica. A notification that appeared on Facebook for some users Tuesday told them that "one of your friends" used Facebook to log into a now-banned personality quiz app called "This Is Your Digital Life." The notice says the app misused the information, including public profiles, page likes, birthdays and current cities, by sharing it with Cambridge Analytica.

Berkeley, California - April 10, 2018

1. David Levine watches Mark Zuckerberg testimony in living room at home

2. Levine sitting in chair, watching testimony

3. TV screen showing Zuckerberg testimony

4. SOUNDBITE (English) David Levine, law professor, University of California Hastings College of the Law:

"Mark Zuckerberg had a tall order today. He really had a lot to get done, which is he had to assure members of the Senate that Facebook was on top of the problem, that they had apologized, that they understood the scope of the problems, and that Facebook was taking significant measures to correct those problems. Mr. Zuckerberg also needed to reassure the millions of users around the world that the safety and security of users' data is paramount in the minds of the top officials at Facebook and that they want to make sure that it's as protected as possible."

5. Levine watching Zuckerberg testimony in living room

6. SOUNDBITE (English) David Levine, law professor, University of California Hastings College of the Law:

"He was very good at looking sincere the way he needs to, looking contrite, making eye contact when he needed to, looking down when he needed to look a little - 'I'm hearing you' that sort of thing, so he certainly looked coached. He looked sincere. He looked like he wanted to work with the senators. But he also held his position. If there were issues about will you support a certain type of legislation, where obviously Facebook doesn't really want to support it, he said 'well I agree with the general principle and certainly our team can work with your people,' but when they tried to corner him about ' will you support certain legislation' he wouldn't do it."

7. Zuckerberg on television

8. SOUNDBITE (English) David Levine, law professor, University of California Hastings College of the Law:

"I think he went a long ways toward giving the kind of assurance that Facebook certainly wants to come out of this kind of hearing. I don't think he was nicked too badly. I think there were a couple questions around Cambridge Analytica where he sounded more ignorant, didn't have facts on his fingertips in the way that maybe he should have. But by and large I think at Facebook headquarters they're going to say, certainly at the end of today there still more hearings, but - mission accomplished."

9. Levine watching Zuckerberg testimony in living room