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."