EU chief negotiator Enrique Mora, who coordinated the 2015 text affording Iran sanctions relief in return for curbs on its nuclear activities, is currently in Iran underlining the "urgency of resuming discussions," spokesman Peter Stano said.

"We are awaiting the Iranians' response," he added.

"Josep Borrell is for his part in Washington where he is meeting with his American counterpart Antony Blinken over the Iranian nuclear accord.

"We shall see the outcome of these discussions," said Stano.

US President Joe Biden has signalled a willingness to revive the accord, which has been been on life support since 2018, when then US president Donald Trump unilaterally pulled out, if Iran return to full compliance with the deal.

Indirect negotiations between Washington and Tehran, via intermediaries from other parties to the accord, began in Vienna in April to agree a roadmap to revive the deal but were suspended following the June election of a new hardline Iranian president, Ebrahim Raisi.

"A meeting will be called if all parties are in agreement and are all ready," said Stano. "There is an urgent need to resume discussions very soon."

Mora is coordinating meetings between negotiators and Borrell ministerial meetings.

Blinken on Wednesday warned, however, of "other options" if diplomacy fails, while his visiting Israeli counterpart reserved the right to use force against Tehran.

Blinked said he hoped to see successful talks but warned "the runway that we have left to do that is getting shorter and shorter."

The accord between Iran and the United States, Britain, China, France, Germany and Russia offered Tehran the lifting of some international sanctions in exchange for a ramping down of its nuclear enrichment programme under strict UN supervision.

The US unilateral withdrawal from the accord in 2018 saw Iran progressively abandon its engagements and Washington react by imposing sanctions.