The Iran nuclear agreement cannot be destroyed by the incoming US administration, says a former International Atomic Energy Agency chief, despite president-elect Donald Trump's criticism of the deal during the presidential campaign.

Hans Blix believes Washington "can put obstacles in the way" but stressed, however, that the deal is backed by the entire UN Security Council, so ripping it up could prove very difficult.

Along the campaign trail, Trump issued a variety of statements about last year's pact, calling it "stupid," a "lopsided disgrace" and the "worst deal ever negotiated."

He also railed against its time-limited restrictions on Iran's enrichment of uranium and other nuclear activity, painting US and European concessions in often cartoonish hyperbole.

During the campaign, Trump also appeared to encourage the development of nuclear weapons by other allied states, however Blix believes this will change once he takes office.

"He will realise that if Japan were to move for nuclear weapons - and they could do so in a very short time if they wanted to - that the whole political situation and atmosphere in the Far East would be very, very different," he argued.

Stockholm - 10 November 2016

1. Various of former IAEA (the International Atomic Energy Agency) chief Hans Blix taking part in panel discussion in Sweden about small-arms control

2. Close-up on face of Blix

3. SOUNDBITE (English) Hans Blix, former IAEA chief:

"I think it would be very difficult for the US to extricate (itself) from that (Iran nuclear) agreement. And I think it was to the great credit of Obama and Hillary Clinton that they stood behind it. And I think it gives...if it were not for that agreement, there would be a greater risk that Iran might move towards nuclear weapons."

4. Cutaway

5. SOUNDBITE (English) Hans Blix, former IAEA chief:

"To tear it up (the nuclear agreement between Iran and world powers), I think would be very difficult. Because it is not just a bilateral agreement between the US and Iran. It's also Russia, it's China, it's UK and France, and it is the whole (UN) Security Council that stands behind it. And the UN Security Council have lifted the sanctions. The UN sanctions are no longer there, European sanctions are no longer there. Maybe the US under Trump would obstruct and that they would let their financial institutions to consider powers to prevent transactions in (US) dollars with Iran, so they can put obstacles in the way, but they cannot destroy the agreement."

6. Various cutaways

7. SOUNDBITE (English) Hans Blix, former IAEA chief:

"I think that he will recognise that the world is a lot more dangerous for the US and for everybody if there are more states that have nuclear weapons than less. Trump has made some statements that question this. He said well why shouldn't (the) Japanese have their weapons or South Koreans have their weapons. But I think that better advice and looking at the matter more closely, he will realise that if Japan were to move for nuclear weapons - and they could do so in a very short time if they wanted to - that the whole political situation and atmosphere in the Far East would be very, very different."

8. Cutaway

9. SOUNDBITE (English) Hans Blix, former IAEA chief:

"Now, one has to make some distinction between what politicians say in election campaigns and in other... And I think that he has been very careless in the election campaign. It could come out this way or it could come out that way. But once you are in an institution, there are many factors available to you. You have the big military establishment of the United States: they are not reckless. I may not always agree with them, certainly not, but they are not reckless."

10. Cutaway

11. SOUNDBITE (English) Hans Blix, former IAEA chief:

"We need a detente in the world in order to get back to climate. Whether that will happen under Trump, we don't know, he is a very touchy guy and maybe he is someone to fear that if you step on his toes he will touch the button (nuclear trigger). But he is also someone who thinks very freely, who is not wedded to old doctrines. And that could in some situations be an advantage. One has the impression that he is not keen on interventionism for instance. In that sense similar to Obama - Obama did not intervene in Libya, he did not intervene in Syria, he did not want to have a no-fly-zone in Syria, which Hillary (Clinton) wanted to have. So it's still open questions here."

12. Blix talking after interview