The US will attend international talks on the Iranian nuclear agreement next week in the biggest effort to rescue the landmark deal since Donald Trump abandoned it almost three years ago.

The negotiations in Vienna will be an attempt to bring the agreement “back to life” after President Joe Biden said Washington was prepared to rejoin if Tehran came back into compliance, a senior EU official said.

While no direct talks between officials from Washington and Tehran are anticipated, the presence of both countries at the same gathering would be an important step. The negotiations are expected to focus on how to achieve simultaneous action by the US and Iran so that Trump-era sanctions can be removed at the same time as Tehran starts to re-comply with the limits imposed on its nuclear programme by the accord, diplomats said.

“There is a single exercise, which is how to bring the JCPOA back to life,” the EU official said, referring to the nuclear deal by its formal name, the Joint Comprehensive Plan of Action. “The idea is to define the conditions in which the United States will come back to the JCPOA and Iran will restart full compliance with the agreement.”

The Vienna talks were announced after a meeting on Friday of the remaining signatories to the accord — the EU, Germany, France, the UK, Russia, China and Iran. The 2015 agreement imposed curbs on Iran’s nuclear programme in exchange for the lifting of many international sanctions.

Next week’s discussions are expected to focus solely on restoring the original deal and not cover issues such as Iran’s ballistic missile programme or its role in other Middle Eastern conflicts, which both the US and European powers eventually want to tackle. But negotiating re-engagement on the narrower deal alone has proved challenging, complicated by hardline domestic pressures on both Biden and Iran’s president Hassan Rouhani. Iran is also due to hold presidential elections in June.

Mohammad Javad Zarif, Iran’s foreign minister, underscored the challenges as he appeared to suggest the US should move first before Iran came back into compliance.

The aim of the Vienna negotiations was to “rapidly finalise sanction-lifting and nuclear measures for choreographed removal of all sanctions, followed by Iran ceasing remedial measures”, Zarif wrote on Twitter. “No Iran-US meeting. Unnecessary,” he added.

Diplomats say indirect or “proximate” talks between parties are not unusual, such as in the negotiations on the Dayton accords that ended the 1992-1995 Bosnian war.

Iran told European officials at a meeting in Frankfurt this week that it wanted to agree a road map to take both sides back to full mutual compliance with the deal, three people briefed on the matter said. This has opened the possibility of a more comprehensive approach than previous proposals for “gesture-for-gesture” moves, under which both the US and Iran would offer small concrete concessions straight away.“The US engaged in [the idea of] gesture-to-gesture at Iran’s suggestion,” a US official told the Financial Times. “They [Iran] now want to talk about full compliance — which suits us well since it is consistent with our original stance.”Although the US was open to direct talks, Tehran indicated that it would rather negotiate indirectly through the Europeans, according to the people briefed. Experts in the US said that presented a significant but not insurmountable task.“The positive thing is that once you have the road map at least both sides would no longer have any illusions about what the endgame would look like,” said Ali Vaez, Iran director at the International Crisis Group.But he added it was “going to be painstaking and tough to negotiate a complete road map”.