EU urges Iran to back down from nuclear escalation

"We reject any ultimatums", they added, after Iran threatened to exit the Joint Comprehensive Plan of Action, the 2015 nuclear non-proliferation treaty.

"At the same time we recall our own firm commitments under the agreement including as regards sanctions-lifting," they also said.

They "regretted" an earlier US decision to quit the accord.

And they promised to "continue pursuing efforts to enable the continuation of legitimate trade with Iran" via Instex, a new trade vehicle due to be up and running in June.

The German chancellor, Angela Merkel, echoed the statement in her remarks after an EU summit in Romania the same day.

Iran should avoid "escalation", she said.

She criticised its aggressive rhetoric on Israel and its proxy wars in Syria and Yemen.

She also acknowledged that the Instex project had its "limitations" in circumventing the US sanctions.

But Merkel said Iran could prove it was a responsible player on the world stage by sticking to the 2015 deal.

"By adhering to this diplomatic solution, Iran also has a chance to make it clear that it has a peaceful intention. So it's an added value for Iran, in my view, to continue to commit to this agreement," she said.

The EU spoke out after Iranian president Hassan Rouhani threatened on TV one day earlier to resume uranium enrichment and plutonium production in 60 days unless Europe began doing business with its oil firms and banks.

"After a year of patience, Iran stops measures that the US has made impossible to continue," he said.

But "if the five countries join negotiations and help Iran to reach its benefits in the field of oil and banking, Iran will return to its commitments according to the nuclear deal," he added.

The potential collapse of the JCPoA comes after US president Donald Trump walked out of the deal last year and threatened to impose fines on EU firms that did business with Iran.

The EU-brokered accord, signed also by Russia, was designed to stop a nuclear arms race in the Middle East and the risk of a US or Israeli conflict with Iran that that might entail.

Trump imposed extra sanctions on Iran this week and moved an aircraft carrier to the Persian Gulf, ratcheting up tensions.

'Eat grass'

"The Iranian people do not want to eat grass so that the regime can have a nuclear weapon," Brian Hook, his top Iran envoy, said.

"We will not allow Iran to obtain nuclear weapons ... We will continue to fight those who seek to take our lives," Israeli prime minister Benjamin Netanyahu also said on Iran's uranium ultimatum.

The Instex vehicle, based in Germany, is designed to enable trade in food and medicines, but resumption of oil-buying remains on hold as EU, Indian, and even Chinese firms ponder the potential US backlash.

The "EU statement today is why the JCPoA is where it is: the US has bullied Europe - and the rest of the world - for a year and the EU can only express 'regret'," Iranian foreign minister, Mohammed Javad Zarif, said on Thursday in reaction to the EU's appeal.

"Instead of demanding that Iran unilaterally abide by a multilateral accord, the EU should uphold obligations - including normalisation of economic ties," he added.

Implicit threat

Rohani, the Iranian president, also made an implicit threat on Wednesday to let more heroin and migrants flow to Europe from the region if it did not meet demands.

"You are obliged [to uphold the JCPoA] ... for your own security, for protecting your youths against drugs as well as controlling influx of immigrants," he said.

It was up to "the Europeans, who committed to find a solution to the problem created by the Americans, to fulfill their promise,''Russian foreign minister Sergei Lavrov noted the same day.

But a US treasury official dealing with counter-terrorism, Sigal Mandelker, said the Instex project was doomed to fail due to the American restrictions.

"I question how that [Instex trading] is even remotely possible," he said on Tuesday.

"I think it's extremely complicated for the Europeans to think that they're going to be able to do that ... Where we see sanctionable activity, we're going to take action to confront it," he added.