High Representative of the EU for Foreign Affairs and Security Policy Josep Borrell, gives a press conference in the Iranian capital Tehran, on June 25, 2022. AFP
The negotiations began in Vienna in April last year but hit a snag in March amid differences between Tehran and Washington, notably over a demand by Iran that its Islamic Revolutionary Guard Corps be removed from a US terror list.
Separate, indirect talks between Iran and the United States will be held under EU mediation in a Gulf Arab country to try to hammer out the remaining sticking points, Borrell said.
"We will resume the talks on the JCPOA in the coming days... I mean quickly, immediately," Borrell told a news conference in the Iranian capital, referring to the accord by its formal name, the Joint Comprehensive Plan of Action.
The landmark nuclear 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.
The administration of incumbent US President Joe Biden has sought to return to the agreement, saying it would be the best path with the Islamic republic.
Separate Iran-US talks
"We agreed today that this visit will be followed by the resumption of negotiations also between Iran and the US facilitated by my team to try to solve the last outstanding issues," said Borrell.
Negotiations between Iran and the United States would be held in a Gulf country to avoid confusion with the broader talks in Vienna, he said.
"Because they're bilateral contacts between Iran and the United States, we prefer to do it in a different place," Borrell said.
He said the contacts would begin "sooner than you can imagine" but would be indirect with his EU team on hand to establish contacts.
The JCPOA itself was agreed after initial contacts between Iran and the United States in the neutral Gulf sultanate of Oman, which has long maintained good relations with both parties.
The EU foreign policy chief was speaking after a two-hour meeting with Iran's Foreign Minister Hossein Amir-Abdollahian, on the second day of a previously unannounced visit to Tehran.
Amir-Abdollahian confirmed the resumption of the Vienna talks.
"We will try to solve the problems and differences through the talks that will resume soon," Amir-Abdollahian said, adding the key for Tehran was "the full economic benefit of Iran from the agreement concluded in 2015", in other words the lifting of US economic sanctions.
On the eve of Borrell's trip, the US point man on Iran, Robert Malley, had "reiterated firm US commitment to come back to the deal" over a meal with the EU diplomatic chief, according to the EU's coordinator for the talks, Enrique Mora.
"We remain committed to the path of meaningful diplomacy, in consultation with our European partners," Malley said in a tweet.
In April, Secretary of State Antony Blinken said the United States still believed a return to the accord was "the best way to address the nuclear challenge posed by Iran".
Blinken warned at the time that the "breakout time" for Iran to develop a nuclear bomb if it so chooses was "down to a matter of weeks" after the deal pushed it beyond a year.
The International Atomic Energy Agency's board of governors adopted a resolution this month censuring Iran for failing to adequately explain the previous discovery of traces of enriched uranium at three sites which Tehran had not declared as having hosted nuclear activities.
On the same day, June 8, Tehran said it had disconnected a number of IAEA cameras that had been monitoring its nuclear sites.
IAEA chief Rafael Grossi later confirmed 27 cameras had been disconnected, leaving about 40 still in place.
The move by Iran, he warned, could deal a "fatal blow" to the negotiations unless the UN nuclear watchdog's inspectors were given access within three to four weeks.
During the talks in Vienna aimed at reviving the accord, Iran has repeatedly called for guarantees from the Biden administration that there will be no repeat of Trump's pull-out.
Borrell came to "give a last-ditch ultimatum, declaring that if the negotiations do not lead to an agreement, the failure of the talks will be announced in the days and weeks to come", according to Iranian analyst Ahmad Zeidabadi.
But he told AFP: "I think there are good chances that an agreement can be concluded" because it is in the interest of the various parties.