Powerful new explosions rocked Tehran on Tuesday, the fourth day of the war launched by Israel and the United States, with Donald Trump saying he had "almost destroyed everything" in Iran.

"Their air defense, their air force, their navy and their command are annihilated. They want to talk. I said: 'Too late!'" the American president posted on his Truth Social network.

Iran denied any attempt at an approach, via its ambassador to the United Nations Ali Bahreini, who described the decision to attack in the middle of talks between the two countries as "totally stupid".

In Tehran, a ghost town, Tuesday's strikes notably targeted the institution responsible for electing a supreme leader to succeed Ali Khamenei, who was killed on Saturday at the start of this unprecedented conflict and is to be buried in the holy city of Mashhad, according to Iranian media.

In the capital, AFP journalists saw clouds of smoke rising, particularly in the city center where many government buildings are located.

"I am afraid to walk in the deserted streets because bombs keep falling from the sky," said Samireh, a 33-year-old nurse.

Public radio and television, ballistic missile production sites, Mehrabad airport in the capital: Israel "continues to strike Iran forcefully," declared its Prime Minister, Benjamin Netanyahu.

- Drone attack on the American consulate in Dubai -

In retaliation, Iran announced on Tuesday evening a new salvo of missiles on Israel and is increasing its attacks against its Gulf neighbors, targeting key sites, often linked to American interests.

And it claims not to have yet used its most advanced weaponry.

On Tuesday evening, a drone attack caused a fire near the US consulate in Dubai. Earlier that day, other Iranian drones had struck the US embassy in Saudi Arabia, also causing a fire, as well as oil facilities in Oman and the United Arab Emirates.

In Bahrain, an American airbase was targeted by drones and missiles, and in the evening, detonations were heard by AFP journalists in Doha, Abu Dhabi and Dubai.

As in Riyadh, the US embassies in Kuwait and Bahrain have closed as a precaution until further notice, and Washington has ordered the departure of all its non-essential diplomatic staff from six countries in the region.

- "Considerable force" -

Since the start of the war, six American service members have been killed, according to the Pentagon. In Israel, according to rescue services, ten people have died in Iranian airstrikes.

On the Iranian side, the Red Crescent announced a death toll of more than 780 people since the start of the attack on Saturday, a figure that AFP was unable to verify.

The Middle East as a whole is ablaze: strikes have taken place in Iraq and Lebanon, drawn into the war by Hezbollah which attacked Israel to "avenge" the death of the Iranian leader, has since suffered massive bombings in Beirut and in the south of the country.

According to Lebanese authorities, a total of 52 people have been killed and more than 58,000 displaced - double the figure given the previous day.

Israel claims to have struck 160 Hezbollah targets since Monday, vowing to continue "with considerable force" until the pro-Iranian movement is disarmed. Its soldiers have also entered Lebanon to take control of a "buffer zone."

"In response", Hezbollah has, for its part, increased its rocket fire, notably against four Israeli military bases.

- "Attack first" -

In his first exchange with White House journalists since the start of the war, Donald Trump denied being drawn into the war by Israel, as his Secretary of State, Marco Rubio, had suggested.

"Given the way the negotiations were going, I think they (Iran) were going to attack first. And I didn't want that to happen. So I may have forced Israel's hand. But Israel was ready. And we were ready," the US president said, adding that "almost everything was destroyed" in the enemy country.

When asked who might lead Iran after the war, he stated that most of the officials Washington had in mind were dead.

The "worst-case scenario" for Tehran would be the arrival of an official "as bad" as Ayatollah Ali Khamenei, he asserted.

At the start of the attack, which resulted in the deaths of several high-ranking officials, Donald Trump called on the Iranian people to overthrow the Islamic Republic that had been in power since 1979.

But if the United States wants the current government to fall, the primary objective is to prevent Iran from acquiring an atomic bomb - an intention Tehran denies - and to destroy its ballistic capabilities, according to Israel.

The Israeli army claimed to have struck a secret underground military center of Iran's nuclear program in the Tehran region, thus eliminating "a key element of the Iranian regime's ability to develop nuclear weapons".

- Market concerns -

Faced with the expansion of this multifaceted conflict, global stock markets are deepening their losses, weighed down by soaring oil prices. European gas prices are also soaring, affected by the halt in liquefied natural gas (LNG) production in Qatar and the paralysis of the Strait of Hormuz.

Revolutionary Guard General Ebrahim Jabbari threatened to launch reprisals against "all regional economic centers," after promising the day before to "burn any ship" that attempted to cross the strait, through which 20% of the world's oil and LNG transit.

The US Navy could escort oil tankers "if necessary," Donald Trump proposed.