Iran has started to inject advanced centrifuges with uranium gas, an Iranian nuclear spokesman has said, in a move that violates the country's 2015 nuclear deal with world powers.
Behruz Kamalvandi, the spokesman for Iran's Atomic Energy Organization, announced the action on September 7, two days after Tehran had signaled it would be taking further steps away from the accord, which the United States abandoned last year but other major signatories have been scrambling to salvage.
He said Iran could not "unilaterally" remain committed to the so-called Joint Comprehensive Plan of Action (JCPOA) between Iran and world powers including China, Britain, France, Germany, and Russia.
"The European parties to the deal should know that there is not much time left, and if there is some action to be taken [to salvage the nuclear deal], it should be done quickly," Kamalvandi said, according to Reuters.
U.S. Defense Secretary Mark Esper said he was not surprised by Tehran's announcement.
"I'm not surprised that Iran has announced that it's going to violate the JCPOA, they have been violating it," he said next to French Defense Minister Florence Parly at a news conference in Paris, according to dpa.
"It's no surprise that the Iranians are going to pursue what the Iranians always intended to pursue," Esper added.
Parly said Paris would continue to do everything it could to save the nuclear deal.
Kamalvandi also said Tehran would be working on "new types of centrifuges."
"Right now we don't need it, but developing new types of centrifuges is in our agenda," he added in a televised appearance, according to Reuters.
Such moves could reduce the time needed for Iran to amass enough material for a nuclear weapon if it wanted to build one.
Tehran has insisted for years that, despite Western accusations and indications of previous covert military aims, its nuclear ambitions are merely civilian.
It has repeatedly said its "steps" away from the JCPOA are reversible.
Tehran announced on September 6 that it had shed limits on its research and development under the deal.
It had already reportedly breached stockpile and enrichment levels within the agreement.
Kamalvandi said that Iran "will continue the cooperation with the international nuclear agency also in this new phase and will not limit access of IAEA inspectors to our facilities," according to dpa.
The acting director of the International Atomic Energy Agency (IAEA), Cornel Feruta, was expected to meet with high-level officials in Iran on September 8 to discuss Iran's plans.
Russia's permanent representative to international organizations in Vienna, Mikhail Ulyanov, said the news from Iran "shouldn't be overdramatized."
"Yes, it's another deviation from #JCPOA, but new activities will remain verifiable by #IAEA and reversible. No proliferation threat. Just a strong signal that balance within the JCPOA must be restored," he said via Twitter.
Iranian President Hassan Rohani warned earlier this week that Tehran's imminent steps away from the 2015 accord "will have extraordinary effects."
U.S. President Donald Trump last year abandoned the deal that gave Iran access to world trade, including the sale of oil, in exchange for curbs on its nuclear program.
Amid mounting tensions, European powers this week called on Iran to avoid any action that contravenes its commitments to the deal.
The French Foreign Ministry said on September 5 that Iran "must refrain from any concrete action that is not in line with its commitments and that may hinder deescalation efforts."
European Commission spokesman Carlos Martin Ruiz de Gordejuela urged Iran to "reverse these steps and refrain from further measures that undermine the nuclear deal."