Iran begins a transition process on Sunday after the death of Supreme Leader Ali Khamenei, killed by US-Israeli strikes.

This process involves the formation of a provisional Steering Committee comprising the Iranian president, Massoud Pezeshkian, the head of the judiciary, Gholamhossein Mohseni Ejei, and a religious dignitary who is a member of the Assembly of Experts and the Revolutionary Guard Council, Alireza Arafi.

This triumvirate is tasked with ensuring the interim leadership until the election of a new supreme leader.

Another leader is expected to play a major role in this process: the head of the Supreme National Security Council, Ali Larijani.

- The president -

Massoud Pezeshkian, aged 71, was elected president in July 2024 after his predecessor died in a helicopter crash.

This cardiac surgeon turned politician is considered a reformer.

Born in 1954 in Mahabad, in the province of West Azerbaijan (northwest Iran), Massoud Pezeshkian is the son of an Iranian father of Turkish origin and a Kurdish mother.

This technocrat, renowned for his calm demeanor, led the government during two of the most turbulent periods in the history of the Islamic Republic, including the 12-day war in 2025 triggered by an Israeli attack, which the United States joined, and the mass protests of early January.

On Sunday, he stated that the assassination of Ali Khamenei constituted a "declaration of war against Muslims everywhere in the world," believing that avenging his death was a "legitimate right and duty" for Iran.

- The head of the judiciary -

Gholamhossein Mohseni Ejei, a 69-year-old Shiite religious figure, was born in the village of Ejeh, in the province of Isfahan, in central Iran.

An emblematic figure in the judicial and security apparatus of the Islamic Republic, he was appointed head of the judiciary in 2021 by Ali Khamenei.

According to the judiciary's online media outlet, Mizan Online, he completed his Islamic studies in the Shiite holy city of Qom and holds a master's degree in international law.

He holds the religious title of Hojatoleslam, an intermediate rank in the Shiite clergy, below that of Ayatollah.

In 2010, while serving as Minister of Intelligence, he was placed under US sanctions for "serious human rights violations" related to the repression of protests that followed the disputed re-election of President Mahmoud Ahmadinejad in 2009.

"The evil regime of the United States and Zion (Israel, editor's note), humiliated and slandered, must know that the great Iranian nation will never forgive the blood shed by its heroic leader," he said.

- The lawyer-

Alireza Arafi, 65, is second vice-president of the Assembly of Experts, the body responsible for appointing and overseeing the supreme leader, and a member of the Revolutionary Guard Council.

He also heads the country's Shiite seminary management center.

After studying Islamic sciences in Qom, he was, according to his official website, imprisoned at the age of 16 for his opposition to Mohammad Reza Pahlavi, the shah overthrown by the Islamic Revolution.

He is the youngest and least known of the three members of the provisional Steering Committee.

"The nation will continue on the path of revolution and will avenge the blood of the people, the youth and the students," he asserted on Sunday.

- The head of security -

At 68, Ali Larijani is currently the head of the Supreme National Security Council, the highest security body in Iran.

He is credited with having earned the trust of the supreme leader after his long career in the armed forces, the media, and Parliament.

Born in Najaf, Iraq, in 1957, he is the son of a prominent Shiite dignitary close to Ayatollah Ruhollah Khomeini, founder of the Islamic Republic.

A former fighter in the Islamic Revolutionary Guard Corps – the ideological army of the Islamic Republic – during the war with Iraq (1980-1988), he was the main negotiator on nuclear issues facing London, Paris, Berlin and Moscow between 2005 and 2007.

On Sunday, he was the one who presented the post-Khamenei transition plans. He swore on X to strike Israel and the United States "with a force they have never known".