A three-person council will temporarily govern Iran following the death of Supreme Leader Ayatollah Ali Khamenei.

The council, made up of President Masoud Pezeshkian and judiciary chief Gholamhossein Mohseni Ejei, as well as a member of the Guardian Council, will assume responsibility for the transitional phase, Iranian state media reported on Sunday.

The trio will assume Khamenei’s duties until the Assembly of Experts, a body of 88 influential clerics, nominates a successor.

Iranian law states the Assembly of Experts must pick a new supreme leader as soon as possible.

It is unclear who could succeed Khamenei, who was killed in wide-ranging strikes on Iran by the United States and Israel on Saturday.

Meanwhile, the Iranian Cabinet has warned the death of the country's supreme leader Ayatollah Ali Khamenei will not go unanswered.

It comes after Iranian state media confirmed he'd been killed during a wave of US and Israeli air strikes on Iran.

The cabinet called his killing a "great crime" and it's confirmed the head of Iran’s Revolutionary Guard and a top security advisor have also been killed.

State media are reporting at least 200 killed in the attacks, with 100 children reportedly killed in an attack at a primary school in Iran's south.

The Israel Defense Forces said it has struck an additional 30 or more targets in western and central Iran.

This included aerial defence systems, missile launches, regime targets and military command centres.

Flights to and across the middle east are being cancelled as the conflict continues.

And freight is affected too with ships being warned away from the Straight of Hormuz. (dpa/NAN/ABS)