Iran is to restart activities at its controversial Arak heavy-water reactor, the head of the country’s nuclear agency announced on Sunday.
Heavy water can be used to make plutonium, an important ingredient in the construction of nuclear weapons.
Under the terms of the landmark 2015 nuclear accord, Tehran agreed to repurpose the facility towards research and medicine.
But in the latest escalation over the Islamic Republic’s nuclear ambitions, Ali Akbar Salehi, the head of the Iranian Atomic Energy Organisation, told lawmakers on Sunday that it would renege on the commitment, according to the semi-official ISNA news agency.
Tehran has been gradually reducing its compliance with the nuclear deal signed with global powers after President Donald Trump unilaterally pulled the US out of the agreement last year.
The Arak announcement came as Iranian officials met with the remaining signatories to the JCPOA, including the UK, France and Germany, in Vienna to try and salvage the painstakingly agreed accord.
Iranian President Hassan Rouhani said earlier this month that unless European states provided more effective relief from US sanctions, Tehran would take steps to restart the reactor to “the condition you say is dangerous and can produce plutonium.”
Iran was required to destroy key components of the reactor as part of the deal, although Mr Salehi told Iranian television in January that Iran had secretly ordered replacements.
Iran's decision to restart the Arak reactor is part of its strategy of “maximum pressure pushback”, Dr Sanam Vakil, senior research fellow in the Middle East North Africa programme at Chatham House, told the Telegraph.
Analysts believe that Iran may be seeking leverage in the diplomacy with European nations and ahead of a US deadline on Thursday as to whether it will extend sanctions waivers to foreign companies working on Iran’s civilian nuclear regime.
An Iranian official told Reuters that all steps taken so far are “reversible” if other parties to the deal fulfilled their pledges.
“Other parties should accelerate their efforts, otherwise Iran will take a third step,” he said.
Sunday's nuclear deal meeting was significant because “the symbolism of the diplomacy is really important for Iran,” said Ms Vakil.
However, she expressed doubts over whether it would provide a solution for the ailing deal.
A statement issued by the EU after the meeting contained little to suggest a breakthrough had been found.
Instead, it "reaffirmed" the participants' "continued commitment to preserving the JCPOA" and "their strong support and collective responsibility" for projects including that at Arak.
Tensions between Iran and other signatories, particularly the UK, are high following the seizure of an Iranian-flagged tanker off Gibraltar in early July and the seizure by Iranian Revolutionary Guards of a British-flagged tanker two weeks later.
Prior to the meeting in Vienna, Iranian Deputy Foreign Minister Abbas Araghchi called the seizure of the Iranian tanker a “breach of the JCPOA” in comments carried by state TV, while a government spokesman described a plan for a European-led mission to ensure safe shipping through the Strait of Hormuz as “provocative”.
Royal Navy destroyer HMS Duncan arrived in the Gulf Sunday to provide support for frigate HMS Montrose, which operates in the region, until she comes off duty in late August.
“Merchant ships must be free to travel lawfully and trade safely, anywhere in the world,“ said recently appointed Defence Secretary Ben Wallace. ”While we continue to push for a diplomatic resolution that will make this possible again without military accompaniment, the Royal Navy will continue to provide a safeguard for UK vessels until this is the reality.”