BERLIN (AP) -- Diplomats negotiating in Vienna to revive Iran's 2015 nuclear deal with world powers have paused after five days of talks to consult with their governments and will reconvene next week, officials said Friday.
The European Union official chairing the meeting said there had been some progress, but further "convergence" was necessary.
"We have identified the challenges ahead. Now it is time to consult with capitals," EU diplomat Enrique Mora told reporters. "We will be resuming here in Vienna next week."
"We have substantial challenges ahead, time is not unlimited, there is an obvious sense of urgency," he added. "But above all we need a certain convergence of policy to start negotiations.
The so-called Joint Comprehensive Plan of Action, or JCPOA, has effectively been on life support since the United States pulled out under then-President Donald Trump's "maximum pressure" campaign against Tehran in 2018.
The remaining signatories to the nuclear deal -- Iran, Russia, China, France, Germany and Britain -- have been meeting at the Palais Coburg, a luxury hotel where the agreement was signed six years ago. The accord strictly limited Iran's enrichment of uranium in exchange for the lifting of economic sanctions.
A U.S. delegation headed by the Biden administration's special envoy for Iran, Robert Malley, was staying at a nearby hotel and being briefed on the talks by diplomats from the other countries.
The Iranian delegation, appointed by new Iranian President Ebrahim Raisi, this week called for the U.S. to unfreeze $10 billion in assets as an initial goodwill gesture.
Mora said reviving the agreement would require Iran to meet its commitments under the accord, and bringing the United States back into "full compliance," meaning Washington would need to drop the crippling economic sanctions it imposed on Tehran.
Asked what had been achieved this week, Mora said there had been progress "in the sense that we have had a new Iranian delegation, they have engaged in negotiations with other delegations."
"We are incorporating also new policy sensitivities for the new Iranian delegations," he said. "But again, the point of departure, the common ground, is where we finished" during the last round of talks in June.
In the United Arab Emirates, French President Emmanuel Macron expressed doubt that the new round of the struggling negotiations with Iran would succeed but added: "That does not mean the negotiations will not restart, and quickly."
"I think everyone is aware how important it is to continue discussing not just the nuclear deal but other regional issues," Macron said while in Dubai on the first day of a two-day Gulf trip.
France, along with Germany and the U.K., thinks that the 2015 nuclear agreement, with minor tweaks, remains the best way forward with Iran. Israel, and Gulf countries like the UAE and Saudi Arabia, have opposed the agreement.
Since the deal's collapse, Iran started enriching small amounts of uranium up to 60% purity; weapons-grade uranium calls for levels of 90%. Iran also spins advanced centrifuges barred by the accord, and its uranium stockpile now far exceeds the limits set out in the deal.
The International Atomic Energy Agency, which monitors the Islamic republic's nuclear program, reported Wednesday that Iran has taken steps to enrich uranium up to 20% purity at an underground nuclear facility in Fordo where all enrichment activist was supposed to cease.
Iran maintains its atomic program is not designed to produce weapons. U.S. intelligence agencies and international inspectors say Iran had an organized nuclear weapons program up until 2003.
IAEA inspectors are unable to fully monitor Iran's program because Tehran has limited their access to its sites.