Britain, France, and Germany have sought to salvage the pact, under which Iran undertook to curtail its uranium enrichment program in return for relief from sanctions, since the United States withdrew from it in May 2018 and levied “toughest ever” embargoes on the Iranian economy.

But the three European powers have failed to make good on the trade and investment dividends promised to Iran under the deal as they have been unable to shield Tehran from the renewed US sanctions that have strangled its oil trade, as a result, diplomatic path of JCPOA is ruined.

That has prompted Iran to renege step by step from its nonproliferation commitments under the deal.

The International Atomic Energy Agency (IAEA), the UN’s nuclear watchdog, on Monday confirmed that Iran has begun enriching uranium at its Fordo nuclear facility, saying that Tehran’s enriched uranium stock has continued to grow.

“Since 9 November…, Iran has been conducting uranium enrichment at the plant,” the IAEA said in a quarterly report, obtained by Reuters.

The move alarmed European powers that had previously dismissed Tehran’s steps of reducing commitments, such as exceeding the cap on stockpiles of enriched uranium and on the fissile purity of enrichment, as insignificant and reversible.

The Atomic Energy Organization of Iran (AEOI) said last Wednesday that it had officially started injecting gas into hundreds of centrifuges at Fordo in the fourth step away from the nuclear deal.

The step came as part of the fourth rollback of Iran’s commitments under the nuclear deal, officially known as the Joint Comprehensive Plan of Action (JCPOA), in reciprocation for the US pullout from the agreement and Europe’s failure to meet its end of the bargain.

Britain, France, and Germany raised the prospect of a restoration of international sanctions for the first time late Monday after a meeting of foreign ministers in Paris, saying they were ready “to consider all mechanisms … including the dispute resolution mechanism.”

Under the terms of the 2015 deal, if any party believes another is not upholding their commitments they can refer the issue to a Joint Commission comprising Iran, Russia, China, the three European powers, and the European Union.

If the complaining party cannot resolve the matter at the Commission level, it could then notify the UN Security Council, which must vote within 30 days on a resolution on continuing Iran’s sanctions relief.

If this is not adopted within that time span, sanctions that were in place under previous UN resolutions would be re-imposed — known as a “snapback” — unless the council decided otherwise.

“We don’t want to pull out of the (deal) too soon, but equally we cannot sit back. The Russians and the Chinese are not going to trigger this, but us, as Europeans, will have to take a stance at some point,” said a European diplomat.

“It is not if but when, unless Iran pulls back, but even then, they are gaining (nuclear) knowledge by spinning these centrifuges, so we have to react.”

EU foreign policy chief Federica Mogherini said Monday that despite all difficulties, the bloc’s foreign ministers have once again reaffirmed their support for the full implementation of the JCPOA.

Diplomats said a meeting of the parties to the accord would take place over the next week to discuss the latest developments. However, they say, the Europeans are unlikely to trigger the mechanism before January when Iran is due to announce its next round of steps away from compliance with the deal.

“What we’re now seeing is the dismantling of the JCPOA,” Reuters quoted another diplomat without disclosing their identity.

“We haven’t decided on launching the mechanism, because we need to be sure of how it will help us in trying to defuse tensions. The questions we’re asking are when, how, and whether it benefits us to do it?”

Iranian Foreign Minister Mohammad Javad Zarif reiterated Tuesday that Iran itself had launched a complaint mechanism and was ceasing to heed its deal commitments as the Europeans had failed to protect it from American sanctions.