The Middle East war that began on Saturday was triggered by coordinated US and Israeli strikes on Iran, including one that killed the Iranian supreme leader.

Israel has claimed the strikes were essential to safeguard its own national security, in part because Iran was reconstituting its nuclear weapons programme in a new, underground facility.

Israel's military spokesman Nadav Shoshani said Thursday the strike that killed Khamenei "complied with international law".

"Under the international law of armed conflict, military commanders directing armed forces during war can constitute lawful military targets," Shoshani said on X.

"As Iran's Supreme Leader, Ali Khamenei served as Commander-in-Chief of the Iranian Armed Forces," he added, describing the ayatollah as "the final decision-maker on Iran's military operations".

"During the ongoing conflict, he directed the use of force against Israel and oversaw the funding, arming, and coordination of the regime's terror proxies...

"Neutralizing the regime's Commander-in-Chief delivered a clear military advantage by degrading Iran's ability to plan and coordinate attacks against Israel," Shoshani said.

Iranian media have reported that Khamenei's wife, son-in-law, and two grandchildren who were minors also died in the strike that killed the ayatollah.

Iran has responded to his killing by launching waves of missile attacks on Israel and targets across the Middle East, including US military and diplomatic sites.

Israel and the United States have continued to bomb targets in Iran.