Iran questions Trump's understanding of nuclear deal after US threatens non-recertification

The President of Iran has questioned US President Donald Trump's understanding of a 6-nation agreement that would lift crippling economic sanctions in return for limitations to the country's controversial nuclear energy programme, after Trump threatened to withhold his signature from its recertification, saying "apparently he doesn't know that this agreement is not a bilateral agreement solely between Iran and the United States."

Congress requires the US president to certify every 90 days that Iran is upholding its part of the agreement. Trump had already recertified it twice, but refused to sign a third time ahead of Sunday's  deadline.

Global powers, including key US allies, have stated their intention to honour the Iran nuclear deal, originally struck by former US President Barack Obama and which US President Donald Trump has threatened to scrap. On Friday Trump announced that he would stop signing off on the agreement.

In response, the UK, France and Germany said that the agreement had been entered into as a matter of “shared national security interest". The EU also pointed out that it was "not up to any single country to terminate" a "working" deal. China has not spoken since the speech but has previously called on the US to preserve the agreement. Russia's foreign ministry expressed regret at Trump's decision but said it did not expect this to stop the deal from being implemented.

Describing the US as “more isolated than ever,” Iran's President Hassan Rouhani questioned whether it was even possible for a party to single-handedly annul a multilateral international treaty. "Apparently he doesn't know that this agreement is not a bilateral agreement solely between Iran and the United States."

The deal, signed in 2015, between Iran and six international powers - the UK, the US, Russia, France, Germany, and China, imposed restrictions on Iran's nuclear programme in return for an easing of international sanctions.

In a speech on Friday, Trump called Iran a "fanatical regime" and said it had violated the terms of the deal and accused it of sponsoring terrorism. He proposed new sanctions.

"We will not continue down a path whose predictable conclusion is more violence, more terror, and the very real threat of Iran's nuclear breakout," he said.

International observers say Iran has been in full compliance with the agreement.

European diplomats warned that any such unilateral changes to the agreement were likely to trigger the deal's collapse and a return to a nuclear standoff in the Middle East. EU foreign policy chief Federica Mogherini said that Europe and the world could not afford to terminate a nuclear deal that was working well.