Talks to revive the Iran nuclear deal will resume within days after being stalled for months, the EU's top diplomat, Josep Borrell, said on Saturday, during a surprise visit to Tehran.
The indirect negotiations between Tehran and Washington, in which the UK is participating, began in April last year, but hit a snag in March, particularly over a demand by Iran that its Islamic Revolutionary Guard Corps be removed from a US terror list.
Foreign Secretary Liz Truss had previously said that the talks were Iran's "last chance" to revive the deal and that if they fail, "all options are on the table” to prevent the regime from gaining nuclear weapons.
Following the talks in Tehran, Mr Borrell appeared to have reached an agreement to restart negotiations.
"We will resume the talks on the JCPOA [Joint Comprehensive Plan of Action] in the coming days," he told a news conference in the Iranian capital. While he did not provide a specific date, he added: "I mean quickly, immediately".
The landmark nuclear deal reached with Britain, China, France, Germany, Russia and the United States gave Iran relief from sanctions in return for guarantees that it could not develop an atomic weapon.
But the deal has been hanging by a thread since 2018, when then US president Donald Trump unilaterally withdrew from the accord and began imposing harsh economic sanctions on America's arch enemy.
Incumbent President Joe Biden has sought to return to the agreement.
Following Mr Borrell's announcement, Iran's Foreign Minister Hossein Amir-Abdollahian said: "We will try to solve the problems and differences through the talks...We hope that specifically the US side, this time around, realistically and fairly makes responsible and committed efforts in the negotiations".
Iran has always denied wanting a nuclear arsenal.
But the International Atomic Energy Agency this month censured Iran for failing to adequately explain the discovery of traces of enriched uranium at three sites that Tehran had not declared as having hosted nuclear activities.
Iran also disconnected a number of IAEA cameras that had been monitoring its nuclear sites, which the agency warned could deal a "fatal blow" to the negotiations.
The visit by Mr Borrell, his first to Tehran since February 2020, could be a determining factor in the fate of the deal.