Iran said it would soon exceed limits on its enriched uranium stockpile agreed in a nuclear deal with world powers, increasing the urgency of European efforts to save the landmark accord.

The breach, which Tehran said would happen within 10 days, threatens to push the 2015 agreement to total collapse following US president Donald Trump’s withdrawal from the pact last year.

It will also stoke already elevated tensions between the Islamic republic and Washington. The White House responded to Iran’s announcement on Monday by accusing it of engaging in “nuclear blackmail”.

The Atomic Energy Organisation of Iran said the country’s production of uranium enriched to a low level had increased fourfold and its stockpile would pass a 300kg limit by June 27th.

Iran could also increase its enrichment of uranium above a purity of 3.67 per cent, the level agreed under the accord, the agency added. Increasing enrichment to 20 per cent would be a highly provocative move because it would bring Iran much closer to being able to produce weapons-grade uranium, which requires 90 per cent purity.

The Iranian announcement increases the pressure on the accord’s other signatories – Germany, France, UK, Russia and China – to find ways to counter the impact of crippling US sanctions that Mr Trump reimposed after abandoning the deal.

In May, Hassan Rouhani, Iran’s president, set a 60-day deadline for the signatories to deliver tangible measures to enable Iran to export oil and transact with international banks. The deadline is July 7th.

Washington has been stepping up its pressure on Tehran in recent weeks. Mr Trump accused Tehran of being behind attacks on two oil tankers in the Gulf of Oman last week and US officials have said they suspect Iran was involved in sabotage attacks on four tankers last month.

Little evidence

The US has provided very little evidence for the series of allegations. The Pentagon last week released a video showing what it said were members of the Iranian Revolutionary Guard Corp retrieving an unexploded magnetic mine from the hull of one of the tankers hours after the attacks.

But analysts have said the video does not prove Iran was behind the attacks. One senior US official said the administration had a range of intelligence but that the video in itself was “pretty conclusive” that Iran was responsible. Iran has rejected the allegations.

Iran has not previously breached the nuclear accord, but last month Tehran warned that it would increase its atomic activity as the economy reels from the impact of US sanctions.

While some critics blame Mr Trump’s withdrawal from the nuclear deal for inflaming tensions in the Persian Gulf, the White House laid the blame on the Obama administration and the 2015 deal.

“Iran’s enrichment plans are only possible because the horrible nuclear deal left their capabilities intact,” said Garrett Marquis, spokesman for the White House National Security Council.

“President Trump has made it clear that he will never allow Iran to develop nuclear weapons. The regime’s nuclear blackmail must be met with increased international pressure.”

Iran’s Atomic Energy Organisation said the remaining signatories to the deal still had time to save the accord, but added that the “current conditions cannot continue”. It added that Europe “was killing time or wants to do something but cannot practically do” anything to save the deal.

“We have quadrupled production of uranium. The countdown has begun as of today and Iran will surpass the ceiling of 300kg within the next 10 days on June 27,” the organisation said.

Sanctions risk

If Iran is deemed to be in breach, it would raise the risk of EU and UN sanctions being reimposed on the country. Under the terms of the agreement, Tehran agreed to limit its nuclear activity in return for the economic benefit of having many sanctions lifted. But the reimposition of US sanctions has stymied Iran’s ability to export oil and pushed the economy back into a deep recession.

Ali Vaez, director of the Iran project at Crisis Group, a think tank, said Iran’s preferred option was to remain committed to the accord, adding that its measures so far have been “carefully calibrated” and are still reversible.

“But without any doubt, sooner or later, they will be in technical violation of the deal, and if this pattern of escalation continues, at some point they will be in material breach,” he said. “That would put the remaining parties to the deal in a very difficult situation because if they go to the Security Council and snapback the UN sanctions, the JCPOA [nuclear deal] will be dead, and if they don’t do so, they have lost face.”

Germany, France and the UK – the so-called E3 – have sought to save the deal, which they argue was critical to defusing an international crisis and ease the risk of an arms race in the Middle East.

This year, they launched a payments channel, Instex, in a bid to keep some trade and financial links open. But Instex is not yet operational and its initial focus was to be on food and medicine. – Copyright The Financial Times Limited 2019