Tensions between the US and UK over whether to tear up the Iran nuclear deal were exposed on Thursday when the secretary of state, Rex Tillerson, said the US viewed Iran as being in default of the deal’s expectations but the British foreign secretary, Boris Johnson, urged the world to have faith in its potential to create a more open Iran.

Tillerson repeatedly emphasised that the US decision about whether to end the agreement – signed in 2015 – will be based on a wider assessment of Iranian behaviour, including in Yemen and Syria, and not just on whether Tehran is complying with the strict terms of the deal.

Donald Trump resumed his attacks on the agreement on Thursday, calling it “one of the worst deals I’ve ever seen”.

Trump claimed Iran had “violated so many different elements, but they’ve also violated the spirit of that deal”. He did not say what he would do on 15 October, when Congress requires the administration to certify Iran’s compliance, but said his stance would be “very evident”.

The state department announced on Thursday that the US would continue to suspend nuclear-related sanctions on the Iranian oil industry, as required by the agreement. But officials insisted that the president’s waiver of sanctions did not reflect an endorsement of the deal, known as the joint comprehensive plan of action (JCPOA).

“Waiving some of those sanctions should not be seen as an indication of President Trump or his administration’s position on the JCPOA nor does the waiver give the Iranian regime a pass on its broad range of malign behaviour,” said the state department’s spokeswoman, Heather Nauert.

The US Treasury imposed new sanctions on 11 individuals and companies for alleged hacking attacks on the US and for trading in components for Iran’s missile programme. Nine of the targets named were Iranian and two were Ukrainian.

Johnson and Tillerson, speaking at a joint press conference in London, were united in urging the leader of Myanmar, Aung San Suu Kyi, to speak out against the massacre of Rohingya Muslims.



But the two men were clearly at odds over Iran. The UK and the other signatories of the 2015 deal – France, Germany, Russia and China – remain committed to the agreement. The UN’s nuclear watchdog, the International Atomic Energy Agency (IAEA), has reported that Iran is sticking to its obligations to abide by strict limits on its stockpiles of nuclear material and on its nuclear activities.

If Trump blocks certification of Iranian compliance in mid-October it would cause a substantial rift with Washington’s European allies. But the president has appeared determined to overturn an agreement the Barack Obama administration saw as its signature foreign policy achievement.

The administration must certify to the US Congress every 90 days whether Iran is adhering to the agreement. If Trump refuses to certify compliance Congress has 60 days to decide whether to reimpose the sanctions that were lifted under the agreement.



In April Trump ordered a broad review of Iranian compliance with the 2015 nuclear deal. That review is not yet complete but is reported to recommend maintaining US participation in the agreement. Meanwhile hardliners inside and outside the White House are urging Trump to ditch the deal and take a much more confrontational stance towards Iran.



The Trump administration has repeatedly claimed that Iran is violating the spirit of the nuclear agreement. Tillerson quoted the agreement’s preamble as saying the signatories “anticipate that full implementation of this JCPOA will positively contribute to regional and international peace and security”. He claimed that Iran was in default of that clause by “propping up the Assad regime, by engaging in malicious activity in the region, through its cyber activity and by aggressively developing ballistic missiles.

“We have to consider the totality of Iran’s activities and not let our view be defined solely by the nuclear agreement.”

European diplomats reject such an interpretation of the deal, saying it was clear at the time the agreement was signed that it was solely about Iran’s nuclear programme and was designed to prevent chronic tensions in the region turning into a nuclear arms race.

Johnson agreed that “the Iranians have got to behave and fulfil their side of their bargain. They have got to stop their adventurist and expansionist plans, causing trouble in Yemen, Syria or anywhere else”.

But in a markedly different tone he added: “On the other side, we in the UK feel that Iran – a country of 80 million people, many of them young and potentially liberal – could be won over. I think it is important they see there are benefits from the JCPOA, so we in the UK want that alive.”

On Myanmar, Johnson made it clear that he could no longer defend Aung San Suu Kyi, the Nobel peace prizewinner. Last week he described her as “one of the most inspiring figures of our age” as he urged her to stop violence against the Royhingha.

In a sign he has lost his patience, he said: “Let’s be clear: she led Burma after a period of decades of repression by a military junta and I yield to no one in my admiration of what she stood for and the way she fought for democracy. I think many people around the world share that admiration.

“But I think it’s now vital for her to use that moral capital and that authority to make the point about the suffering of the people of Rakhine. Nobody wants to see a return to military rule in Burma, nobody wants to see a return of the generals.

“But it is vital for her now to make clear that this is an abomination and that those people will be allowed back to Burma and that preparation is being made and that the abuse of their human rights and the hundreds, perhaps even thousands, of killings will stop.”

Attacks by Rohingya militants on security posts last month provoked an army operation that has killed more than 400 people, destroyed over 6,800 houses and sent nearly 400,000 fleeing to Bangladesh.