If confirmed, the death of Ali Larijani would represent a major blow to Iran, whose long-serving leader Ayatollah Ali Khamenei was killed less than three weeks ago in US-Israeli strikes that ignited a war in the Middle East.

The reported assassination came as Iran's speaker vowed that shipping in the Strait of Hormuz would not return to its pre-war norm, and Donald Trump blasted allies for rebuffing his call to help escort oil tankers through the blockaded waterway.

Tehran has not confirmed the death of Larijani, described as a key figure close to the late ayatollah, but urged Iranians across the country to rally Tuesday in a show of defiance against enemy "plots".

Israel's military vowed it would also eliminate Iran's new supreme leader, Mojtaba Khamenei, the son of the late ayatollah who took power after his father's death on February 28.

"We don't know about Mojtaba Khamenei, we don't hear him, we don't see him, but I can tell you one thing: we will track him down, find him, and neutralise him," military spokesman Brigadier General Effie Defrin told reporters.

- 'Right hand man' -

In a televised statement, Israeli Prime Minister Benjamin Netanyahu described Larijani as "the boss of the Revolutionary Guards, which is the gang of gangsters that actually runs Iran".

He said the overthrow of Iran's authorities by the people "will not happen all at once, it will not happen easily. But if we persist in this -- we will give them a chance to take their fate into their own hands."

While Mojtaba Khamenei has not been seen in public since he was appointed, Larijani, 68, walked with crowds at a pro-government rally last week in Tehran.

"He has effectively been the figure in charge of the regime's survival, its regional policy and its defence strategy," David Khalfa, co-founder of the Atlantic Middle East Forum, told AFP.

"It's the supreme leader who gives the order, but he is the one who carries it out. He is the right-hand man."

Shortly after Israel said it had killed him, Larijani's official social media profiles posted a handwritten note by him paying tribute to Iranian sailors killed in a US submarine attack this month.

The note was not dated, nor did the post address the claim of his death.

Images on Iranian state television showed large crowds rallying from the early evening in Tehran and other cities, many waving the nation's flag, on a night usually marked by festive Persian new year celebrations.

AFP journalists reported muted Nowruz celebrations in Tehran, with some fireworks and crackers heard between shots from air defence systems.

Israel's military said it was striking positions of Iran's Basij paramilitary force around Tehran on Tuesday, after announcing it had killed group's top commander, Gholamreza Soleimani.

Iran's Revolutionary Guards confirmed Soleimani's death in a statement Tuesday evening.

Israel earlier said it had also targeted Akram al-Ajouri, head of the military wing of the group Palestinian Islamic Jihad, in a strike in Iran.

Since the October 7, 2023 croos-border attacks by Hamas into Israel from Gaza, Israel has pursued what analysts have described as a policy of decapitation, targeting the leaders of its enemies.

Turkey's Foreign Minister Hakan Fidan on Tuesday called these assassinations "truly illegal".

- Trump scolds allies -

Iran has retaliated by targeting its US-allied Gulf neighbours and all but closing the Strait of Hormuz through which a fifth of global crude passes, sending oil prices soaring.

"The Strait of Hormuz situation won't return to its pre-war status," Mohammad Bagher Ghalibaf said in an English-language social media post on Tuesday.

Oil prices surged after several countries pushed back on Trump's demand they help secure the strait by sending warships to escort tankers.

Trump accused NATO of making a "foolish mistake" by refusing to help and said the US no longer needed assistance in reopening the strait.

"Because of the fact that we have had such Military Success, we no longer 'need,' or desire, the NATO Countries' assistance -- WE NEVER DID! Likewise, Japan, Australia, or South Korea," Trump posted on his Truth Social network.

"WE DO NOT NEED THE HELP OF ANYONE!" he added.

His comments came moments after President Emmanuel Macron said France was ready to help once the situation was calmer but stressed his country was "not a party to the conflict", echoing other EU and NATO leaders.

A top US counterterrorism official resigned to protest the war, arguing that Iran had posed no imminent threat to the United States.

- Sleeping in cars -

Countries from the Gulf to Lebanon and Iraq were pummelled by airstrikes, with AFP journalists reporting loud explosions Tuesday evening in capitals across the region.

The war has also drawn in Lebanon, after Tehran-backed Hezbollah militants struck Israel over Khamenei's killing.

Israel has stepped up strikes and deployed ground troops to its northern neighbour, and the Lebanese military says six of its soldiers have been killed so far.

More than a million people have been displaced across Lebanon, while Israeli strikes have killed 886 people since March 2, Lebanon's health ministry says.

In the southern city of Sidon, displaced people were sleeping in their cars, according to an AFP team on the ground.

"Lots of people are coming every day to ask for shelter but we don't have space anymore, we can't accept them," said Jihan Kaisi, the director of an NGO that runs a school-turned-shelter, where more than 1,100 people are crammed together.

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