Iran has declared that it will no longer abide by any of the restrictions imposed by the 2015 nuclear deal.
In a statement it said it would no longer observe limitations on its capacity for enrichment, the level of enrichment, the stock of enriched material, or research and development.
The statement came after a meeting of the Iranian cabinet in Tehran.
It comes amid heightened tensions over the killing of Iranian General Qasem Soleimani by the US in Baghdad.
Under the 2015 accord, Iran agreed to limit its sensitive nuclear activities and allow in international inspectors in return for the lifting of crippling economic sanctions.
US President Donald Trump abandoned it in 2018, saying he wanted to force Iran to negotiate a new deal that would place indefinite curbs on its nuclear programme and also halt its development of ballistic missiles.
Iran refused and has since been gradually rolling back its commitments under the agreement.
Earlier on Sunday, Iraqi MPs passed a non-binding resolution calling for foreign troops to leave the country after the killing of Soleimani in a drone strike at Baghdad airport on Friday.
About 5,000 US soldiers are in Iraq as part of the international coalition against the Islamic State (IS) group.
The coalition paused operations against IS in Iraq just before Sunday’s vote.
What did Iran say?
A statement broadcast on Iranian state TV said the country would no longer respect any limits laid down in the 2015 deal.
“Iran will continue its nuclear enrichment with no limitations and based on its technical needs,” the statement said.
It did not, however, say that Iran was withdrawing from the agreement and it added that Iran would continue to co-operate with the UN’s nuclear watchdog, the IAEA.
The statement added that Iran was ready to return to its commitments once it enjoyed the benefits of the agreement.
Correspondents say this is a reference to its inability to sell oil and have access to its income under US sanctions.
Iran has always insisted that its nuclear programme is entirely peaceful.
The other parties to the 2015 deal – the UK, France, Germany, China and Russia – have tried to keep the agreement alive. But the sanctions caused Iran’s oil exports to collapse and the value of its currency to plummet, and sent its inflation rate soaring.