"Time is running out," said Jerome Bonnnafont at a UN Security Council meeting, in reference to the October expiration of the 2015 Iran nuclear deal.

"We expect Iran to return to talks without delay in order to achieve a robust, verifiable and lasting diplomatic solution," he added.

Bonnafont said negotiations were the only way to "guarantee the impossibility of an Iranian military nuclear program," days after the United States conducted strikes against Iranian nuclear facilities.

"France and its E3 partners (Germany and the United Kingdom) remain ready to use the leverage established by Resolution 2231, that of a 'snapback' (of sanctions), if a satisfactory agreement is not reached by summer," he warned.

UK ambassador Barbara Wood concurred, saying: "We will use all diplomatic levers at our disposal to support a negotiated outcome, and ensure Iran does not develop a nuclear weapon."

UN Security Council Resolution 2231 endorsed the 2015 agreement Iran reached with the E3 countries, as well as China, Russia and the United States, to regulate its nuclear program in return for eased sanctions.

President Donald Trump removed the United States from the agreement in 2018.