Iran has announced it will breach on 27 June the limit on its stockpile of enriched uranium that was set under a 2015 nuclear deal with world powers.
Its atomic energy agency said it had quadrupled production of the material, which is used to make reactor fuel and potentially nuclear weapons.
But it added there was “still time” for European countries to act by protecting Iran from reinstated US sanctions.
The UK, France and Germany have warned Iran not to violate the deal.
They have previously said they will have no choice but to reimpose their own sanctions, which were lifted in return for limits on the Iranian nuclear programme.
Reuters news agency quoted a US National Security Council spokesman as saying the enrichment plans were “nuclear blackmail” and should be met with “increased international pressure”.
“Iran’s enrichment plans are only possible because the horrible nuclear deal left their capabilities intact,” Garrett Marquis said.
“President Trump has made it clear that he will never allow Iran to develop nuclear weapons.”
This latest development comes at a time of high tension in the Middle East, with the US accusing Iran of being behind suspected attacks that left two oil tankers ablaze in the Gulf of Oman on Thursday. Iran has denied any involvement.
