BERLIN -- 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 Joint Comprehensive Plan of Action has effectively been on life support since the United States pulled out under then-President Donald Trump's "maximum pressure" campaign 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.
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 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" in June at the last round of talks.
The deal saw Iran limit its enrichment of uranium in exchange for lifting of sanctions.
Since the deal's collapse, Iran now enriches small amounts of uranium up to 60% purity -- a short step from weapons-grade levels of 90%. Iran also spins advanced centrifuges barred by the accord, and its uranium stockpile far exceeds the accord's limits.
On Wednesday, the International Atomic Energy Agency that monitors the Islamic republic's nuclear program said Iran has begun steps to enrich uranium at an underground nuclear facility in Fordo -- where it was meant to halt all enrichment -- up to 20% purity.