The Israeli military has said it carried out several wide-scale waves of strikes across Iran, as supporters of the Islamic Republic staged rallies to celebrate the appointment of a new supreme leader.

Mojtaba Khamenei, a hardline Shia Muslim cleric close to the powerful Revolutionary Guards, was chosen on Sunday to succeed his father, Ayatollah Ali Khamenei, who was killed in a strike at the start of the war with the US and Israel nine days ago.

In his first reaction to the decision, US President Donald Trump said he was "not happy".

Meanwhile, Iran launched new barrages of missile and drones at Gulf Arab states hosting US military bases and Israel, where one person was killed on Monday.

The price of oil also surged to more than $100 a barrel for the first time in four years, with the war disrupting exports and forced production stoppages in the region.

Iranian state TV announced late on Sunday that Mojtaba Khamenei had been elected the new supreme leader by the Assembly of Experts, a body of 88 Shia clerics.

On Monday, authorities called on people to gather in major squares and streets across the country to "pledge allegiance" to the 56-year-old.

Videos published by Iranian media showed rallies in Tehran, Bojnurd, Tabriz, Zanjan, Kerman, Khorramabad, Mashhad, Bushehr, Yazd, Qom and Ilam.

Thousands took part in a rally in the capital's Enghelab Square, chanting "Death to America, death to Israel" and "God is greatest" under a banner bearing a portrait of Ali Khamenei and the words "Your path will continue".

A teenager told Iran's Student News Network (SNN) that the appointment showed that the Iranian people are "alive and will not back down".

But a man in his 30s told BBC Persian that "even the thinnest of chances for a change are no more", adding that supporters of the establishment "don't even need to change their chants".

On Sunday night, some social media users had shared footage reportedly showing people in Tehran chanting "Death to Mojtaba" from their balconies. They echoed chants against his father that were heard during the nationwide protests in January, when thousands of people were killed in a crackdown by security forces.

Little is known about Mojtaba Khamenei, who has never held an official position. However, he is known to have been heavily involved in running his father's office, with influence over politics, security, foreign affairs and the economy.

The Islamic Revolution Guard Corps (IRGC) quickly pledged its allegiance to him, while the secretary of Iran's Supreme National Security Council, Ali Larijani, said his appointment had "caused the hostile and warmongering enemies to despair.

Israel's foreign ministry dismissed Mojtaba Khamenei as "another tyrant to continue the Iranian regime's brutality".

Before Sunday's announcement, the US president had warned that any leader chosen without his approval "isn't going to last long".

Asked about his plans for the new supreme leader on Monday, Trump told the New York Post: "Not going to tell you. I'm not happy with him."

He later told CBS News that the war was "very far ahead" of his initially stated schedule of four or five weeks.

"I think the war is very complete, pretty much," he said. "They have no navy, no communications, they've got no air force."

On Monday evening, Trump said the US had "won in many ways, but we haven't won enough".

The US military said on Monday that it had struck 5,000 targets during the conflict, including more than 50 Iranian vessels, as well as air defence systems, ballistic missile sites, and military communications.

The Israeli military announced that its fighter jets had carried out extensive strikes on military infrastructure in Tehran, Isfahan in central Iran, and Shiraz in the south during Monday.

It said they struck a command centre in Tehran belonging to the Quds Force, the IRGC's overseas operations arm, and a site in Isfahan used for the manufacturing and storage of anti-aircraft missiles and other defence systems.

The military also said six major Iranian military airfields were targeted, along with the IRGC's drone headquarters and ballistic missile production infrastructure.

Residents of eastern Tehran told BBC Persian that they heard explosions as the rallies in support of Mojtaba Khamenei were taking place in Enghelab Square.

Iranian state TV also reported a blast near a gathering of loyalists in the historic Naqsh-e Jahan square in Isfahan. Footage showed people waving flags and chanting "God is greatest" as a cloud of smoke rises into the sky in the background.

There was no immediate response from Iranian authorities.

However, the Iranian Red Crescent said on Monday afternoon that its first responders were trying to rescue two people and remove bodies from a destroyed building in Resalat Square in north-eastern Tehran.

At least 1,230 people have been killed across Iran since the start of the conflict, according to the humanitarian organisation. It has not said whether the figure includes members of the armed forces.

The US-based Human Rights Activists News Agency (HRANA) has put the reported death toll at 1,708, including 1,205 civilians and 187 military personnel.

Iran has responded to the US and Israeli strikes by launching hundreds of missiles and drones at Israel and neighbouring Gulf Arab states which host US military bases.

On Monday, authorities in Israel reported the first deadly strike there in just over a week.

A worker from China was killed and another was seriously injured by shrapnel from a missile with a cluster bomb warhead at a construction site in Yehud, local media reported.

A third person was injured elsewhere as at least six locations in central Israel were reportedly hit by cluster bombs from the same missile.

Footage shared on social media in recent days has shown the use of such warheads, which break up into smaller bombs, making them difficult for air defences to intercept as they scatter over a wide area.

In Bahrain, the health ministry said at least 32 citizens were injured overnight in an Iranian drone attack on the Sitra area, south of the capital, Manama. Four people were seriously injured, including a two-month-old baby and 17-year-old girl.

Another Iranian strike caused a fire and material damage at the kingdom's Al Maameer oil facility.

And in the United Arab Emirates, the defence ministry said two members of the armed forces were killed when their helicopter crashed "due to a technical malfunction while performing their national duty".

The Qatari interior ministry at the same time said 313 people of various nationalities had been arrested on suspicion of "spreading misleading information and rumours" during the Iranian attacks, including by filming and circulating unauthorised videos.

On Saturday, Iran's president apologised to neighbouring countries for attacking them.

However, he later clarified his remarks following a backlash from Iranian hardliners, saying Iran would be "forced to respond" to any attack originating from their soil.

Qatari Prime Minister Mohamed bin Abdul Rahman Al Thani said in an interview with Sky News that he "totally rejected" Iran's attempts to justify the attacks.

French President Emmanuel Macron meanwhile said that his country and its allies were preparing for a "defensive" mission to reopen the Strait of Hormuz.

Iran has sought to block the narrow Gulf waterway, through which about 20% of global oil and gas shipments pass, since the start of the conflict.

In response to Macron's remarks, Larijani said security in the strait was unlikely to be restored "amid the fires ignited by the United States and Israel in the region". (BBC)

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