U.S. and Iranian officials could hold nuclear discussions within coming weeks under a plan by the European Union to bring the two sides together for the first time since President Biden took office, according to U.S. officials and senior diplomats.

The move, potentially a first step toward reviving the 2015 international nuclear agreement, came after Secretary of State Antony Blinken discussed the deepening nuclear standoff with the foreign ministers of Britain, France and Germany. Former President Donald Trump withdrew from the accord. U.S. officials said Washington was on board with the plan.

Iranian officials didn’t respond to a request for comment. They haven’t agreed to participate in such talks, according to senior diplomats.

According to the diplomats, the idea would be to hold an in-person meeting in the next few weeks of all remaining participants in the deal—Britain, France, Germany, Russia, China and Iran—with the U.S. invited as a guest.

No date has yet been set for a meeting, which could be convened in the next few weeks, the diplomats said. However they warned the idea doesn’t yet have buy-in from all sides, including Iran.

State Department officials said Thursday the U.S. special envoy for Iran, Robert Malley, likely would attend a meeting if one is held. One of the officials said they doubt that either the U.S. or Iran is going to take measures to lower tensions in advance of the meeting and that if the talks do happen, it would be a meaningful moment but may not lead to an immediate breakthrough.

“That is the right next step to sit down and talk about all these issues,” the official said.

The plan was denounced by a key congressional Republican.

“It is concerning the Biden administration is already making concessions in an apparent attempt to re-enter the flawed Iran deal,” said Rep. Michael McCaul of Texas, senior Republican on the House Foreign Affairs Committee. “The Trump administration created leverage for President Biden on Iran—we should not squander that progress.”

The potential resumption of diplomacy comes as Iran prepares another in a series of steps away from compliance with the terms of the 2015 deal. Iran has formally told the United Nations’ atomic agency that it plans to tightly restrict the access of international inspectors from Feb. 23 if the U.S. doesn’t drop its sanctions first.

In recent weeks, Iran has started producing uranium enriched to 20% purity —considered to be a relatively short step away from weapons-grade fuel. Iran also has started producing uranium metal, material which can be used in the core of a nuclear weapon.

Top Iranian officials have said in recent days that they will only return to compliance with the accord after the U.S. acts to lift the sweeping sanctions Mr. Trump imposed after withdrawing from the nuclear deal in 2018. They also have said they wouldn’t talk directly with the U.S. until sanctions are lifted, but left open the option of multilateral discussions.

After Mr. Blinken’s videoconference with European counterparts on Thursday, a senior EU official, Enrique Mora, said on Twitter that the nuclear deal is “at a critical moment.”

“Intense talks with all participants and the U.S.,” he wrote. “I am ready to invite them to an informal meeting to discuss the way forward.” The EU chairs the Joint Commission, a body that oversees compliance with the deal.

In a joint statement, Mr. Blinken and the European foreign ministers expressed their grave concerns about these recent steps. However Mr. Blinken reiterated the Biden administration’s desire to re-enter the nuclear deal and said it was ready for talks with Iran to that effect.