Iran’s supreme leader has warned “the battle begins” in an alarming escalation of the language around the conflict with Israel.

“In the name of the noble Haidar, the battle begins,” Ayatollah Ali Khamenei posted on X at dawn on Tuesday (local time).

“We must give a strong response to the terrorist Zionist regime. We will show the Zionists no mercy,” he wrote in a separate post on his English-language account.

They were Khamenei’s first public statements since US President Donald Trump called for Iran’s unconditional surrender, and warned that US patience was wearing thin.

Elsewhere, Iranian state TV has warned of a “major surprise tonight”, one it claims the world will “remember for centuries”.

Trump wrote on his Truth Social account earlier on Tuesday that the US knows “exactly where the so-called ‘Supreme Leader’ is hiding”.

“He is an easy target, but is safe there — We are not going to take him out (kill!), at least not for now. But we don’t want missiles shot at civilians or American soldiers. Our patience is wearing thin. Thank you for your attention to this matter!

A minute later, he added, “UNCONDITIONAL SURRENDER!”

Trump met his national security team in the Situation Room at the White House on Tuesday, officials have said.

There are reports that more than 30 US aerial refuelling tankers have been sent to the Middle East. Sources have told CNN that Trump’s thinking is shifting to using the US military to strike Iran, although he remained open to a diplomatic solution to the days-old conflict with Israel.

He is said to be considering sending his Middle East Envoy, Steve Witkoff, or Vice President JD Vance to meet Iranian officials.

It came as intense Israeli air strikes targeted Tehran for a fifth day in a conflict that Washington-based group Human Rights Activists says has killed at least 585 people across Iran and wounded 1326 others.

It identified 239 of those killed in Israeli strikes as civilians and 126 as security personnel.

Israeli Defence Minister Israel Katz said Khamenei could face the same fate as Iraqi President Saddam Hussein, who was toppled in a US-led invasion and eventually hanged after a trial.

“I warn the Iranian dictator against continuing to commit war crimes and fire missiles at Israeli citizens,” Katz told top Israeli military officials.

Khamenei’s main military and security advisers have been killed by Israeli strikes, leaving major holes in his inner circle and raising the risk of strategic errors, according to five people familiar with his decision-making process.

The Israeli military said Iran’s military leadership was “on the run” and that it had killed Iran’s wartime chief of staff Ali Shadmani overnight, four days after he had replaced another top commander killed in the strikes.

Vance said any decision on further action to end Iran’s uranium enrichment program, which some countries suspect is aimed at developing a nuclear bomb, “ultimately belongs to [Trump]”.

Israel launched its air war on Friday after saying it had concluded that Iran was on the verge of developing a nuclear weapon.

Iran denies seeking nuclear weapons and has pointed to its right to nuclear technology for peaceful purposes, including enrichment, as a party to the Non-Proliferation Treaty.

Israel, which is not a party to the NPT, is the only country in the Middle East widely believed to have nuclear weapons.

Israel does not deny or confirm that.

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

-AAP