PARIS — Iran has less than three weeks to resume talks on its nuclear program or face the reimposition of sanctions, France, Germany and the U.K. said in a joint letter sent to the United Nations.

The so-called E3 countries said they would trigger the “snapback mechanism should no satisfactory solution be reached by the end of August 2025,” in a letter sent last week and shared by French Foreign Minister Jean-Noël Barrot on Wednesday.

Snapback mechanisms were included in the 2015 Iran nuclear deal — which the U.S. unilaterally withdrew from three years later under Donald Trump’s first presidency. They allow for crippling sanctions against Tehran — which were lifted as part of the agreement — to be automatically reinstated if Iran violates key nuclear commitments.

Last month, E3 members warned they could reintroduce sanctions over Iran’s nuclear program, which Tehran is seeking to rebuild following American and Israeli airstrikes in June. The European Commission has, meanwhile, proposed extending the sanction pause to give Iran time to “meet their legal obligations,” without laying out a specific time.

“Since 2019, Iran has willfully and publicly departed from its [nuclear deal] commitments, as evidenced by more than 60 [International Atomic Energy Agency] reports over 6 years,” said the E3 letter, which was co-signed by U.K. Foreign Secretary David Lammy and German Foreign Minister Johann Wadephul alongside Barrot.

“If Iran continues to violate its international obligations, France and its German and British partners will reimpose global embargoes on arms, nuclear equipment, and banking restrictions at the end of August, which were lifted 10 years ago,” Barrot added in a post on X.

Iran severed ties with the International Atomic Energy Agency, the U.N.’s nuclear watchdog, after a 12-day war with Israel, which included U.S. airstrikes on its nuclear facilities.

After the strikes, the IAEA’s head said Tehran would be able to resume nuclear enrichment in a matter of months despite the damage. The agency’s deputy director returned to Iran for the first time since the attacks to resume talks this week, Iranian news agency IRNA has reported.

In their letter, E3 members call for “direct negotiations between Iran and the U.S.” to “resume urgently.”