BRUSSELS — Talks in Vienna aimed at reinvigorating the Iran nuclear deal that the Trump administration left in 2018 and which Tehran began breaking a year later made some progress this week: They didn’t break down.
Senior diplomats involved in the talks agreed on Friday that initial steps in two working groups designed to bring both the United States and Iran back into compliance with the accord were positive and would continue next week.
Although there are no direct talks between Iran and the United States, the other signatories to the deal — Britain, China, France, Germany and Russia, under the chairmanship of the European Union — are engaging in a kind of shuttle diplomacy between them.
One working group is focusing on how to lift the harsh economic sanctions that the United States imposed that are inconsistent with the terms of the nuclear deal, known formally as the Joint Comprehensive Plan of Action, or J.C.P.O.A. The other working group is focusing on how Iran can return to the limits on enriched uranium and the centrifuges to produce it under the terms of the deal.
Briefing journalists on Friday evening, a senior State Department official said that not all sanctions that were imposed against Iran during the Trump administration would be lifted — deliberately leaving open the possibility that economic penalties targeting the Central Bank or any terrorism activities would remain in place.
But the Biden administration is struggling to unwind the web of sanctions imposed by Mr. Trump that, the official said, sought to obscure which penalties were related to the nuclear deal and which were not. If Iran continues to insist that all sanctions are lifted, the official warned, the negotiations are headed for an impasse.
Mikhail Ulyanov, the Russian representative to the talks in Vienna, said in a Twitter message after Friday’s meeting that “participants took stock of the work done by experts over the last three days and noted with satisfaction the initial progress made.” The senior diplomats who meet in what is known as the Joint Commission — representing all signatories except the United States — will reconvene next week “in order to maintain the positive momentum,” Mr. Ulyanov said.
The Iranian representative, Abbas Araghchi, the deputy foreign minister, said that the Joint Commission would meet again on Wednesday. In the meeting, he emphasized Iran’s commitment to the talks and that “this depends on the political will and seriousness of the other parties, otherwise there will be no reason to continue the negotiations,” according to comments posted on Twitter by the Iranian journalist Abas Aslani.
On Thursday, Mr. Araghchi told Iran’s Press TV that he saw hopeful signs from Washington about sanctions relief, but that “I think we have a longer road ahead, although we’re moving forward and the atmosphere is constructive.”
But a spokesman for Iran’s Atomic Energy Organization said this week that Iran has now produced 55 kilograms, or around 120 pounds, of uranium enriched to 20 percent and within another eight months could reach 120 kilograms. In mid-February the amount was some 17.6 kilograms, which is indicative of why the other powers want to move quickly to bring Iran back to the limits mandated in the deal. Iran is also using advanced centrifuges and making uranium metal, both banned under the deal.
U.S. officials have worked to play down expectations for any quick breakthrough and have urged patience. Ned Price, the State Department spokesman, has said that the United States is prepared to lift all the sanctions reimposed and new ones imposed by President Donald Trump after May 2018 that are “inconsistent” with the nuclear deal.
Some of the sanctions Mr. Trump imposed are under terrorism and human rights legislation and are not specifically nuclear-related, and it is possible that Washington will try to keep some of them. Harsh sanctions against Iran’s Central Bank, for instance, imposed in September 2019, are under terrorism legislation. But analysts believe that Iran will not accept leaving that sanction in place.
In what has been perceived as a gesture of good will, Iran on Friday released a South Korean oil tanker that had been held since January in a dispute over billions of dollars seized by Seoul in response to punishing American sanctions.
Iran had accused the ship, the MT Hankuk Chemi, of polluting the waters in the Strait of Hormuz, but the seizure was widely seen as an attempt to put pressure on Seoul to release billions of dollars in Iranian assets tied up in South Korean banks in response to U.S. sanctions on Iran.
The European Union said in a statement after Friday’s meeting that “participants took stock of the discussions held at various levels since the last Joint Commission in view of a possible return of the U.S.” to the nuclear deal and “discussed modalities to ensure the return to its full and effective implementation.”
The commission “was briefed on the work of the two expert groups on sanctions lifting and nuclear implementation measures and participants noted the constructive and results-oriented exchanges.”
Lara Jakes contributed reporting from Washington.