Iran’s president has warned European partners in its faltering nuclear deal that Tehran will increase its enrichment of uranium to “any amount that we want”, beginning on Sunday.
The move puts pressure on Europe to offer a way around intense US sanctions targeting the country.
The comments by President Hassan Rouhani come as tensions remain high between Tehran and the US over the deal, which President Donald Trump pulled America from more than a year ago.
Authorities on Monday acknowledged that Iran had broken a limit placed on its stockpile of low-enriched uranium.
An increasing stockpile and higher enrichment shrinks the estimated one-year window Iran would need to produce enough material for a nuclear bomb, something Tehran denies it wants but the nuclear deal sought to prevent.
The US has rushed an aircraft carrier, B-52 bombers and F-22 fighters to the region and Iran recently shot down a US military surveillance drone.
Speaking at a cabinet meeting in Tehran, Mr Rouhani’s comments seemed to signal that Europe has yet to offer anything to alleviate the pain of the renewed US sanctions targeting its oil industry and senior officials.
Iran’s nuclear deal bars it from enriching uranium above 3.67%, which is enough for nuclear power plants but far below the 90% needed for weapon-grade levels.
“In any amount that we want, any amount that is required, we will take over 3.67%,” Mr Rouhani said.
“Our advice to Europe and the United States is to go back to logic and to the negotiating table,” he added. “Go back to understanding, to respecting the law and resolutions of the UN Security Council. Under those conditions, all of us can abide by the nuclear deal.”
On Tuesday, European powers separately issued a statement over Iran breaking through its stockpile limit, calling on Tehran “to reverse this step and to refrain from further measures that undermine the nuclear deal”.
Under the nuclear deal, Iran agreed to have less than 300kg of uranium enriched to a maximum of 3.67%. Iran and the UN’s nuclear watchdog agency confirmed on Monday that Tehran had breached that limit.
While that represents Iran’s first major departure from the accord, it still remains likely a year away from having enough material for a nuclear weapon. Tehran insists its programme is for peaceful purposes, but the West fears it could allow Iran to build a bomb.
Meanwhile on Wednesday, relatives of those killed in the 1988 shooting down of an Iranian passenger jet threw flowers into the Strait of Hormuz in mourning.
The downing of Iran Air flight 655 by the US Navy remains one of the moments the Iranian government points to in its decades-long distrust of America.
Just after dawn on July 3 1988, the USS Vincennes sent a helicopter to hover over Iranian speedboats the Navy described as harassing commercial ships. The Iranians allegedly fired on the helicopter and the Vincennes gave chase, the Navy said.
Unacknowledged for years afterwards by the Navy, the Vincennes had crossed into Iranian territorial waters in pursuit. It began firing at the Iranian ships there.
The Vincennes then mistook Iran Air flight 655 – which had taken off from Bandar Abbas, Iran, heading for Dubai in the United Arab Emirates – for an Iranian fighter jet. It fired missiles, killing all 290 people on board.
The US later gave USS Vincennes Capt. William C Rogers the country’s Legion of Merit award, further angering Iran.