Mojtaba Khamenei, the son of Iran’s late supreme leader Ayatollah Ali Khamenei, has been named to succeed his father, Iranian state television announced Sunday, following the elder Khamenei’s death in the opening wave of U.S.-Israeli airstrikes that began the current conflict.

The younger Khamenei had long been viewed as a potential successor despite holding no formal government post and maintaining a low public profile. His selection comes after days of speculation and reports of divisions among Iranian officials as the 88-member Assembly of Experts — the body of clerics responsible for choosing Iran’s supreme leader — deliberated over the succession.

There has been only one previous transfer of power in the office since the Islamic Revolution nearly five decades ago.

As supreme leader, Khamenei will hold sweeping authority within Iran’s political system. The country’s powerful Islamic Revolutionary Guard Corps answers to the supreme leader, who serves as commander-in-chief of the armed forces and has the final say over major matters of state and war strategy. The position also holds ultimate authority over Iran’s nuclear policy and its stockpile of highly enriched uranium.

His succession has already drawn criticism from President Trump. “Khamenei’s son is unacceptable to me,” Mr. Trump said, adding that he wants a role in determining who ultimately leads Iran after the war. In an interview with ABC News, Mr. Trump said a new Iranian leader “is not going to last long” without U.S. approval.

Mr. Trump’s comments came as debate grows in Washington over whether the United States could expand its role in the conflict. Some analysts have suggested the possibility of deploying U.S. troops or special operations forces if the war escalates further.

But Sen. Thom Tillis, North Carolina Republican, warned Sunday that sending American forces into combat in Iran would require a new Authorization for the Use of Military Force from Congress.

The fighting has already caused heavy casualties across the region. Iranian officials say more than 1,200 people have been killed in Iran since the conflict began, while additional deaths have been reported in Lebanon, Israel and Gulf states struck by Iranian missiles and drones.

The conflict has also rattled global energy markets. The Strait of Hormuz — through which roughly one-fifth of the world’s petroleum supply passes — has become increasingly dangerous for shipping, helping push crude oil prices above $90 a barrel.