Iran has appointed Mohammad Bagher Zolghadr, a former Islamic Revolutionary Guard Corps officer, as its new security chief after the killing of Ali Larijani.
Mr Zolghadr was appointed secretary of the Supreme National Security Council, taking office as Iran fights a full-scale war with the US and Israel.
When Mr Larijani held the role, he was regarded as one of the most influential men in Iran and a close confidant of the supreme leader. Mr Larijani was assassinated by Israel last week.
Like many of Iran's ruling elite, Mr Zolghadr has held an array of roles in government and the military during a decades-long career.
His military roles included a spell as deputy commander of the IRGC, the loyalist army that has launched waves of missiles at Israel and Gulf countries. As a brig gen, he was appointed by Ayatollah Ali Khamenei in 2007 to work with the Basij, a paramilitary force that suppresses internal dissent.
During the 2000s, he served as deputy interior minister under hardline president Mahmoud Ahmadinejad, whose policies pushed Iran into a nuclear stand-off with the West. Mr Zolghadr also held senior positions in Iran's judiciary.
Most recently, he was appointed in 2021 as secretary of the Expediency Discernment Council, one of the many layers of Iran's complex regime.
Among the council's jobs is to advise the supreme leader, currently Ayatollah Mojtaba Khamenei. Mr Zolghadr is under sanctions by the UK, US and European Union, with some listings citing his role on the council as influential in Iran's nuclear programme.
Although rarely quoted in public, he surfaced a day after Hamas's attacks on Israel on October 7, 2023, to celebrate what he called a "turning point" for Palestinians. "This operation is the starting point of the fall of the Zionist regime," he said.
Iranian state television hailed Mr Zolghadr on Tuesday as bringing "decades of experience across Iran's military, security, and judicial institutions to the post at a critical juncture".
The security role has been held by some of Iran's most prominent politicians. They include former president Hassan Rouhani, Khamenei aide Ali Shamkhani and ultraconservative politician Saeed Jalili.
Mr Larijani had held the role in the 2000s before returning to the post last year, after Israel's 12-day war with Iran. As tension with the US mounted, he was seen as one of Ali Khamenei's closest aides, charged with ensuring the survival of the regime.
He was able to do so for less than three weeks before Israel killed him in Tehran. His killing also eliminated one of the few people seen as a conceivable negotiating partner for US President Donald Trump.
Israel has continued its campaign of assassinations since then, notably killing Intelligence Minister Ismael Khatib, meaning Mr Zolghadr is expected to be a target.
