Iran announced on Sunday that it had chosen a successor to Supreme Leader Ali Khamenei, who was killed on the first day of the US-Israeli offensive launched on February 28 against the Islamic Republic.

The Assembly of Experts, the Iranian body responsible for electing the top leader, has not revealed the name of the successor to Ali Khamenei, who had been in power since 1989.

For the past week, the name of his son, Mojtaba Khamenei, considered one of the most influential figures in the government, had been circulating among the contenders. The name of Hassan Khomeini, the grandson of the founder of the Islamic Republic, Ayatollah Ruhollah Khomeini, has also been mentioned for this position traditionally reserved for a religious leader.

Israel has already announced on Wednesday that the new supreme leader would be "a target".

As for Donald Trump, who at the beginning of the war urged the Iranian people to overthrow the Islamic Republic, he announced on Thursday that he would not accept Mojtaba Khamenei taking over. Washington, which seeks the fall of the regime, has stated its objective as destroying Iran's ballistic missile capabilities and preventing it from acquiring a nuclear weapon—an intention Tehran denies having.

The appointment of the new supreme leader comes as Iran, still reeling from intense strikes, continues to retaliate and claims to be ready for "at least six months of war".

A black veil of smoke blanketed Tehran on Sunday, and a strong smell of burning permeated the city. The Israeli army said it had struck "several" fuel tanks used, according to them, by Iran "to power its military infrastructure," and said it was launching strikes against military sites "across Iran" that morning.

This is the first reported attack on Iranian oil infrastructure since February 28.

Nearby, security forces in raincoats, to protect themselves from toxic fallout, and with respirators on their faces, are filtering traffic. The windows of the surrounding residential buildings have been completely shattered by explosions.

Fuel distribution is now limited to 20 liters per vehicle. Long lines stretched along gas stations in Tehran, AFP observed on Sunday, the first day back in Iran after a week-long holiday declared following the death of Ali Khamenei.

"The fire has been burning for over twelve hours, the air has become unbreathable," testified a resident contacted by telephone from Paris. "The war is spreading. This is not what we wanted. We didn't want them to bomb our national resources and make us even poorer than we already are."

According to the latest figures from the Iranian Ministry of Health, more than 1,200 people have been killed and more than 10,000 civilians injured, claims that AFP has not been able to verify.

- "Precision strike" -

Meanwhile, thousands of kilometers away, the heart of the Lebanese capital was hit overnight. According to the Ministry of Health, Israel struck a hotel in the Raouche district, on the popular tourist waterfront area that had previously been spared from Israeli airstrikes.

Israel described a "precision strike" against "senior commanders" of the Quds Force, the foreign operations branch of the Islamic Revolutionary Guard Corps. It also announced the deaths of two of its soldiers in southern Lebanon.

The new death toll from the Israeli strikes has risen to 394, according to the Health Minister.

- Gulf countries targeted -

The Israeli army said it carried out 3,400 strikes in one week. Washington reported 3,000.

Iran retaliates by launching missiles and drones at infrastructure in the Gulf, a region rich in hydrocarbons and home to several American military bases.

Kuwait reported two deaths and strikes on fuel tanks at its airport, and Bahrain reported damage to a desalination plant.

In Saudi Arabia—the world's second-largest oil producer after the United States, with Iran among the top ten—a drone attack targeted the diplomatic quarter of Riyadh, which the Saudi government claims was thwarted. Another strike targeted the Shaybah oil field in the southeast of the country.

Iran's Revolutionary Guards, the ideological army, also claimed on Sunday to have fired missiles towards Israeli cities and an airbase in Jordan, while explosions were heard in Abu Dhabi, according to witnesses speaking to AFP.

The head of the Arab League describes Iran's attacks on its neighbors as "irresponsible".

In Israel, rescue services reported six injured.

- Warning from Pezeshkian -

Iranian President Massoud Pezeshkian reiterated on Sunday that "if the enemy tries to use the territory of a country to launch an aggression against our territory, we will be forced to retaliate."

The war has spread throughout the region, with repercussions reaching as far as Cyprus, an EU member state, where a British airbase was struck on March 2 by an Iranian-made drone and where French President Emmanuel Macron will travel on Monday.

China and Russia, for their part, have largely remained on the sidelines despite their close ties with Tehran. Experts consider it unlikely, despite the impact on its oil imports, that China will sacrifice its interests and stand up to the United States to come to the aid of its Iranian partner.

"The war in the Middle East should never have happened," Chinese Foreign Minister Wang Yi said on Sunday.

The conflict is paralyzing a large part of the hydrocarbon flows from the Gulf. The Strait of Hormuz remains at the center of concerns, with some 20% of the world's oil production and nearly 20% of liquefied natural gas (LNG) usually passing through it.