President Donald Trump on Tuesday called for Iran's "unconditional surrender" and warned that US patience was wearing thin, but said there was no intention to kill Iran's leader "for now", as the Israel-Iran air war raged for a fifth day.

Israeli Defence Minister Israel Katz said meanwhile that Iran's Supreme Leader Ayatollah Ali Khamenei could face the same fate as Iraqi President Saddam Hussein, who was toppled in a US-led invasion and hanged in 2006 after a trial.

Explosions were reported in Tehran and the city of Isfahan in central Iran, while Israel said Iran had fired more missiles towards it late Tuesday, and air raid sirens sounded in Tel Aviv and southern Israel. The Israeli military said it had conducted strikes on 12 missile launch sites and storage facilities in Tehran.

Trump's comments, delivered via social media, suggested a more aggressive stance toward Iran as he weighs whether to deepen US involvement.

"We know exactly where the so-called 'Supreme Leader' is hiding," he wrote on Truth Social. "We are not going to take him out (kill!), at least not for now...Our patience is wearing thin." Three minutes later, he posted, "UNCONDITIONAL SURRENDER!"

Britain's leader said there was no indication that the US was about to enter the conflict.

Trump met with his National Security Council Tuesday afternoon to discuss the conflict, a White House official said.

The US is deploying more fighter aircraft to the Middle East and extending the deployment of other warplanes, three US officials said.

The US has so far only taken defensive actions in the current conflict with Iran, including helping to shoot down missiles fired towards Israel.

Israeli Prime Minister Benjamin Netanyahu has stressed that he will not back down until Iran's nuclear development is disabled, while Trump says the Israeli assault could end if Iran agrees to strict curbs on enrichment.

But Israel will struggle to deal a knock-out blow to deeply buried nuclear sites like Fordow, which is dug beneath a mountain, without the US joining the attack, according to analysis echoed by Germany's leader.

Iran has so far fired nearly 400 ballistic missiles and hundreds of drones towards Israel, with about 35 missiles penetrating Israel's defensive shield and making impact, Israeli officials say.

The Iranian news agency Tasnim reported that a new wave of drone and missile attacks was launched by the Iranian Air Force against Israeli targets.

The Iranian army also announced the downing of 28 enemy drones.