Western powers vowed over the weekend to forge ahead with efforts aimed at reviving the Iran nuclear deal as capitals scrambled to unpick the implications of the election of Ebrahim Raisi, a conservative cleric and judiciary chief, as Iran’s president.

Negotiators in Vienna on Sunday adjourned talks aimed at restoring the accord. In Brussels the EU said it stood ready to work with Iran’s new government, insisting that “it is important that intensive diplomatic efforts continue to bring the [Joint Comprehensive Plan of Action] back on track.”

US officials insisted on Sunday that the election of the hardline president had not reduced the Biden administration’s desire to revive the Iran nuclear pact.

Jake Sullivan, national security adviser to US president Joe Biden, told ABC News: “Our paramount priority right now is to prevent Iran from getting a nuclear weapon. We believe that diplomacy is the best way to achieve that, rather than military conflict. And so, we’re going to negotiate in a clear-eyed, firm way with the Iranians to see if we can arrive at an outcome that puts their nuclear programme in the box.”

He added that Iran’s supreme leader would be the person who ultimately decided whether the country went back into the nuclear deal, not the country’s president.

But Naftali Bennett, Israel’s new rightwing prime minister, who took office last week, warned on Sunday that it was “the last chance for the world powers to wake up before returning to the nuclear agreement, and to understand who they are doing business with”.

Speaking at his first cabinet meeting, he added: “These guys are murderers, mass murderers. A regime of brutal hangmen must never be allowed to have weapons of mass destruction that will enable it to not kill thousands, but millions.”

Israel has been implacably opposed to the resurrection of the nuclear deal with Iran. It sees the hand of Iran behind its main adversaries in the region — Hamas, the militant group that controls the Gaza Strip, and Hizbollah, the Lebanese Shia faction and the biggest political and military force in Lebanon.

Raisi will take office in early August after winning the election on Friday, replacing Hassan Rouhani. Iran has been seeking to restore the 2015 nuclear accord and shake itself free of US sanctions. The election gives regime hardliners full control of all branches of the state, casting an extra layer of uncertainty over an already-complex process.

Raisi said during his campaign that his government would continue the nuclear talks, and Iranian analysts say the regime needs sanctions to be lifted if the incoming president is to have any chance of fulfilling his promise of easing economic hardship in the republic.

But a regime insider told the FT that hardliners would want to negotiate on their own terms and would not shift on Tehran’s insistence that Iran’s support for militant groups across the region and the expansion of its increasingly sophisticated missile programme are not up for negotiation.

Raisi is much more in line with the thinking of Ayatollah Ali Khamenei, the supreme leader who has the final say on all key foreign policy and security decisions, than Rouhani, who signed the nuclear deal in 2015 and sought to improve ties with the west.

A Raisi government is unlikely to try to cool relations with the US beyond resolving the nuclear stand-off. Former US president Donald Trump quit the deal back in 2018 and reimposed sanctions on Iran.

Tehran has since breached the accord’s limits on uranium enrichment, stoking anxieties in European capitals about prospects for the pact, under which Iran accepted curbs on its nuclear programme in exchange for the lifting of many international sanctions.

Esfandyar Batmanghelidj, visiting fellow at the European Council on Foreign Relations, said the election victory should not have an immediate impact on the Vienna talks, adding that US re-entry into the nuclear deal remained in Iran’s strategic interests.

But he warned that the victory would change the trajectory of diplomacy in the medium term. “A Raisi administration is unlikely to pursue such a ‘more-for-more’ deal, and Raisi’s personal history and the possible conduct of his administration could lead to objections over broader negotiations among many in the west, citing human rights concerns.”

Negotiators for Iran and six remaining signatories — the EU, Germany, France, the UK, Russia and China — have been seeking since April to figure out how to restore the accord and pave the way for the US to rejoin,

A spokesperson for the US state department said: “Our Iran policy is designed to advance US interests, regardless of who is in power. We would like to build on the meaningful progress achieved during the latest round of talks in Vienna.”

Additional reporting by Michael Peel in Brussels