US Secretary of State Michael Pompeo on Sunday threatened Iran with "further isolation and sanctions" hours after Tehran announced that it will "in a few hours" begin enriching urum beyond the limit set in its 2015 nuclear deal with world powers.
"Iran's latest expansion of its nuclear program will lead to further isolation and sanctions. Nations should restore the longstanding standard of no enrichment for Iran's nuclear program. Iran's regime, armed with nuclear weapons, would pose an even greater danger to the world," he tweeted.
Officials were quoted by several media reports as saying that Iran was ramping up the level of urum enrichment beyond the 3.67 per cent permitted under the deal.
Earlier this month, Iran had increased its stockpile of low-enriched urum beyond the cap set by the deal.
The move was a part of an Iran effort to press Europe to salvage the accord after the US pulled out from it in May last year and reimposed punishing sanctions on Tehran, including on its oil and banking sectors, Al Jazeera reported.
Tehran has also threatened to abandon more nuclear commitments unless the remaining signatories of the deal -- the UK, China, Germany, France and Russia -- took steps to evade sanctions, especially to sell its crude.
Responding to the development, the International Atomic Energy Agency (IAEA) said it was aware of Iran's threats, but was waiting for its inspectors in Iran to report to its Vienna headquarters "as soon as they verify the announced development."
Iran's Foreign Minister Mohammad Javad Zarif said that Iran's moves were "reversible" if the European countries upheld their commitments to save the deal.
He said that the three EU signatories -- Germany, France and the UK -- have no pretexts to avoid a firm political stance to preserve the agreement and counter US unilateralism.
"Today, Iran is taking its second round of remedial steps under Para 36 of the JCPOA. We reserve the right to continue to exercise legal remedies within JCPOA to protect our interests in the face of US #EconomicTerrorism. All such steps are reversible only through E3 compliance," Zarif wrote on his Twitter post.
"Having failed to implement their obligations under JCPOA--incl after US withdrawal--EU/E3 should at minimum politically support Iran's remedial measures under Para 36, incl at IAEA. E3 have no pretexts to avoid a firm political stance to preserve JCPOA & counter U.S unilateralism," he added.
The nuclear agreement was signed with an aim to limit Iran's civilian energy programme, thereby preventing it from developing nuclear weapons at some point in the future, in exchange for relief from sanctions that were crippling the country's economy.
The US' decision of pulling out from the agreement soured its ties with Iran. In the past year, the Donald Trump administration slapped a multitude of sanctions on Tehran citing the latter's support to state-sponsored terrorism and conflicts.
( With inputs from ANI )