Israeli rescuers said Tuesday three people were killed in an Iranian strike, as Tehran's state media reported new waves of missiles heading for Israel after US President Donald Trump announced a ceasefire between the two Middle East foes.

Neither Iran nor Israel have confirmed the agreement touted by Trump on ending the conflict that has killed hundreds in Iran and two dozen in Israel.

The US leader had said the ceasefire would be a phased 24-hour process beginning at around 0400 GMT Tuesday, with Iran unilaterally halting all operations. Israel would follow suit 12 hours later.

"It has been fully agreed by and between Israel and Iran that there will be a Complete and Total CEASEFIRE," Trump wrote on his Truth Social platform.

"Upon the 24th hour, an official end to the 12-day war will be saluted by the world," he said, adding that both sides had agreed to remain "peaceful and respectful" during each phase of the process.

Iran's Foreign Minister Abbas Araghchi that "as of now, there is NO 'agreement' on ceasefire or cessation of military operations."

"However, provided that the Israeli regime stops its illegal aggression against the Iranian people no later than 4 am Tehran time, we have no intention to continue our response afterwards," he said on social media.

But Israel's army said sirens were activated in northern Israel -- where moments before Iran's state media Irib reported a wave of missiles were headed.

Israeli emergency services also reported casualties in an Iranian missile strike in southern Israel.

"Following the missile impact site in southern Israel: So far, MDA teams have pronounced the deaths of three people," Magen David Adom said in a statement on X.

Explosions also continued to rock Tehran overnight, with blasts in the north and centre of the Iranian capital described by AFP journalists as some of the strongest since the conflict broke out.

Any cessation in hostilities would come as a huge relief to world leaders frantic about an escalation in violence igniting a wider conflagration.

The adversaries had been swapping missile fire since Israel carried out surprise "preemptive" strikes against Iran on June 13, targeting nuclear and military sites, and prompting Trump to warn of a possible "massive" regional conflict.

- Strikes on US base -

The US leader's truce announcement came hours after Iran launched missiles at the largest US military facility in the Middle East -- Al Udeid Air Base in Qatar -- in a move Trump shrugged off as "very weak."

Calling for a de-escalation, Trump said Tehran had given advance notice of the barrage.

Iran's National Security Council confirmed having targeted the base "in response to the US aggressive and insolent action against Iran's nuclear sites and facilities".

But it added that the number of missiles launched "was the same as the number of bombs that the US had used" -- a signal that it had calibrated its response to be directly proportional rather than escalatory.

"This was calibrated and telegraphed in a way that would not result in any American casualties, so that there is an off ramp for both sides," Ali Vaez, a senior advisor at the International Crisis Group, told AFP.

The offensive came after the United States joined its ally Israel's military campaign against Iran, attacking an underground uranium enrichment centre with massive bunker-busting bombs and hitting two other nuclear facilities overnight Saturday into Sunday.

As international concern mounted that Israel's campaign and the US strikes could ignite a wider conflict, French President Emmanuel Macron insisted that "the spiral of chaos must end" while China warned of the potential economic fallout.

- 'Blatant aggression' -

Iran said its assault in Qatar wasn't targeting the Middle Eastern neighbour, but the government in Doha accused Tehran of "blatant aggression" and claimed its right to a "proportional" response.

Iran's state media quoted the Revolutionary Guard Corps announcing that six missiles had hit Al Udeid, which had been evacuated beforehand, according to the Qataris.

The broadside was made up of "short-range and medium-range ballistic missiles," a US defence official said.

AFP reporters heard blasts in central Doha and in Lusail, north of the capital, on Monday evening, and saw projectiles moving across the night sky.

Iranians gathered in central Tehran to celebrate, images on state TV showed, with some waving the flag of the Islamic republic and chanting "Death to America".

Qatar earlier announced the temporary closure of its airspace in light of "developments in the region", while the US embassy and other foreign missions warned their citizens to shelter in place.

Israeli strikes on Iran have killed more than 400 people, Iran's health ministry has said. Twenty-four people have died in Iran's attacks on Israel, according to official figures.

Also read: Bombers, deceit and decoys: how US strikes on Iran unfolded

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