Ebrahim Raisi, a conservative cleric, was set for a landslide victory in Iran’s presidential election that would give regime hardliners complete control over all branches of the state for the first time in almost a decade.

Raisi’s two main rivals conceded on Saturday and congratulated the 60-year-old who many Iranians believe is the favoured candidate of Ayatollah Ali Khamenei, the supreme leader.

Official results from Friday’s vote, in which Raisi ran against Mohsen Rezaei, a conservative general, and sole reformist candidate Abdolnaser Hemmati, were expected later on Saturday.

The cleric’s victory means that hardliners, who won a sweeping majority in parliamentary elections last year and control the judiciary and the military, are now at their most powerful since 2013. Reformists, who favour greater engagement with the west, have been pushed to the margins.

The election was held at a critical time for the Islamic republic and the region. The Biden administration is seeking to ease tensions in the Middle East, which were inflamed by Donald Trump’s decision in 2018 to unilaterally withdraw the US from the nuclear accord with Iran and impose waves of sanctions on the nation.

Raisi has said his government would continue negotiations with the deal’s remaining signatories — the UK, France, Germany, Russia and China.

But hardliners will want to negotiate on their own terms as the second and final term of President Hassan Rouhani’s centrist government ends in August. The election of Raisi, who has headed the judiciary for the past two years and was the subject of sanctions by the Trump administration in 2019 as it targeted dozens of senior regime officials, risks complicating those talks.

Raisi’s victory also means that Iran will be even more unlikely to rein in its support for militant groups across the region or curb its expansive missile programme.

President Joe Biden has promised to rejoin the nuclear agreement if Tehran falls back into full compliance with the deal. But his administration is under pressure from US politicians, Israel and Washington’s Arab partners to take a tough line on Iran’s support for militias and its missile programme.

Raisi has said domestic policies would be his priority. He faces the daunting task of reviving an economy crippled by sanctions and the coronavirus pandemic, festering social pressures and a deep sense of disillusionment with the theocratic system among many Iranians.

The schisms in society were underscored by the expected low turnout for a presidential election.

Iranian media reported that conservatives voted in large numbers. But Iranians who want reforms displayed their disillusionment with the theocratic system by staying at home in what pro-democracy activists described as an act of civil disobedience.

A low turnout would undermine the popular legitimacy Iran’s leaders seek to claim from elections at a time when the gap between the regime’s ideology and policies and the aspirations of the youthful population is widening.

Conservative analysts said Raisi would probably be closer to Khamenei’s thinking than Rouhani, who wanted to use the nuclear deal to re-engage with the west before Trump imposed his “maximum pressure” campaign.

Unlike his predecessor, Raisi will not attempt to diminish the role of the powerful Revolutionary Guards, which dominate overseas military operations and control a sprawling economic empire at home.

“Raisi’s background in the judiciary tells us that he is obedient to the ones above him but very strict with those junior to him,” said a reformist politician.

“Two good years in the judiciary is similar to a rosy engagement period. From now on, it’s like after marriage that comes with all the realities and disappointments.”

Raisi has made few comments on foreign policy and has said his focus will be on boosting Iran’s industrial production and easing the economic pressures on Iranians.

Conservatives hope he will bring unity to the ruling system after Rouhani’s final term was blighted by bitter internal clashes. Trump’s hostility towards Iran emboldened hardliners who blamed the centrist government and its reformist backers for trusting the US.

But reformers worry that the hardliners’ victory will exacerbate the country’s problems and set back any lingering hopes of gradual reform.

“Reformists need to get prepared for a tough political era . . . and not to succumb to this result,” said Abbas Abdi, a reformist commentator.