Hardline cleric Ebrahim Raisi will be sworn in as Iran's president on Thursday, with the Islamic Republic's clerical rulers face growing crises at home and abroad.
Iranian television said Raisi, 60, would be inaugurated later on Thursday, two days after winning the formal endorsement of the country's supreme leader to take office following his victory in an election in June.
Raisi, who is under US sanctions over allegations of human rights abuses when he was a judge, has promised to take steps to lift tough U.S. sanctions that have cut Iran's oil exports and have shut it out of the international banking system.
Iran has been negotiating with six major powers to revive a 2015 nuclear deal abandoned three years ago by then US President Donald Trump, who said it was too soft on Tehran.
Under the deal, Iran agreed to curbs on its nuclear programme in return for the lifting of international sanctions, but Trump withdrew from the deal and reimposed sanctions that have crippled Iran's economy. Tehran has since breached limits imposed on its nuclear activities under the agreement.
Like Iran's supreme leader, Raisi has endorsed the nuclear talks, but the mid-ranking Shi'ite cleric is widely expected to adopt a tougher line in talks that have stalled.
Supreme Leader Ayatollah Ali Khamenei has the last say on all state matters including nuclear policy.
Iranian and Western officials have said significant gaps remain to be resolved in the nuclear talks and have yet to announce when the talks will resume.
With economic misery palpable at home and signs of growing anger among Iranians over economic hardships, breaking free of the US sanctions will be Raisi's top economic goal, political analysts say.
Tensions have simmered between Iran and the West after a suspected drone attack last week on an Israeli-managed tanker off the Omani coast that killed two crew members.
The United States, Israel and Britain blamed the incident on Iran. Tehran has denied responsibility, and warned it would respond promptly to any threat to its security.
Iran has also denied involvement in a hijacking incident in the Arabian Sea on Tuesday. Maritime security sources said they suspected Iranian-backed forces were behind the attack on a Panama-flagged tanker and Washington said it believed Iranians hijacked the vessel but was not in a position to confirm.
Appointed by Khamenei to run the judiciary in 2019, Raisi was placed under U.S. sanctions a few months later for the role he allegedly played in the executions of thousands of political prisoners in 1988. Iran has never acknowledged the killings.
Since his election, Raisi has said the US sanctions were imposed on him for doing his job as a judge. Dissidents fear his presidency could usher in more repression in Iran.