Iran's atomic agency spokesman said on Monday the country will surpass its uranium stockpile limit set by a 2015 nuclear deal in the next 10 days.
Behrouz Kamalvandi made the announcement in a news conference broadcasted on state television on Monday.
"Today the countdown to pass the 300 kilogrammes reserve of enriched uranium has started and in 10 days time we will pass this limit," Mr Kamalvandi said.
The accord caps Iran's stock of low-enriched uranium at 300 kg of uranium hexafluoride enriched to 3.67 percent or its equivalent for 15 years.
He spoke to local journalists at Iran's Arak heavy water facility.
Iran's semi-official news agency Tasnim reported on Sunday that Tehran was set to announce further moves to scale back its commitments to the Joint Comprehensive Plan of Action signed with world powers in 2015.
US President Donald Trump withdrew from the accord in 2018, and Iran stopped complying with some commitments of the deal from May.
Last month, Iran said it would start enriching uranium at a higher level, unless global powers protected its economy from US sanctions within 60 days.
Mr Kamalvandi added: "There is still time for the Europeans... But the Europeans have expressed indirectly their inability to act. They should not think that after 60 days (deadline set in May by Iran), they will have another 60-day opportunity."
The west European signatories to the deal - France, Britain and Germany - have defended the nuclear accord as the best way to limit Iran's enrichment of uranium.
Iran has repeatedly criticised delays in setting up a European mechanism that would shield trade with Iran from US sanctions in an effort to save the nuclear deal.
The development comes as an Iranian politician warned on Monday that the country will withdrawal from the non-proliferation treaty, which aims to combat the spread of nuclear weapons, unless European nations save the nuclear deal.
"There is not much time left until the end of the 60-day ultimatum given by Iran to the Europeans to save the  deal. After that, Iran will suspend the implementation of the Non-proliferation Treaty," Mojtaba Zolnour, head of parliament's nuclear committee, told the semi-official Fars news agency.
The statement follows a wave of suspected attacks on oil tankers last week in the region, attacks that Washington has blamed on Iran, and also as tensions have spiked between Iran and the United States.
Israeli Prime Minister Benjamin Netanyahu urged world powers on Monday to step up sanctions against Iran swiftly should it go through with a plan to exceed an enriched uranium limit set by a 2015 nuclear deal.
"Should Iran deliver on its threats, the international community will have to implement, immediately, the pre-set sanctions mechanism," Israeli media quoted Netanyahu as saying in a speech following Tehran's announcement earlier on Monday.
The US alleges Iran used limpet mines to target the tankers last Thursday, pointing to black-and-white footage it captured that American officials describe as an Islamic Revolutionary Guard Corps vessel removing an unexploded mine from the Japanese-operated tanker Kokuka Courageous, one of the two ships that were targeted.