Iran has named Mojtaba Khamenei as its new supreme leader, just over a week after the assassination of his father, Ayatollah Ali Khamenei, in joint United States-Israeli strikes that have plunged the entire region into a sprawling war, writes Al Jazeera.

The 56-year-old, who will now be charged with leading the Islamic Republic through the biggest crisis in its 47-year history, was named by clerics as his father`s successor on Sunday.

Key leaders, Iran`s powerful Islamic Revolutionary Guard Corps (IRGC), and the armed forces were quick to pledge their backing to the new leader. Ali Larijani, secretary of the Supreme National Security Council, who has been tasked with steering Iran`s security strategy since the US and Israel launched their all-out offensive, called for unity around the new supreme leader.

Parliament Speaker Mohammad Bagher Ghalibaf welcomed the choice, saying that following the new supreme leader was a "religious and national duty".

Mojtaba Khamenei has never run for office or been subjected to a public vote, but has for decades been a highly influential figure in the inner circle of the supreme leader, cultivating deep ties to the IRGC.

In recent years, Khamenei has increasingly been touted as a top potential replacement for his father. His selection could be a sign that more hardline factions in Iran`s establishment retain power, and could indicate that the government has little desire to agree to a deal or negotiations in the short term as the war enters its second week.