Israeli forces expanded ​their bombardment of Iran overnight, striking fuel depots near Tehran, while Bahrain said an Iranian attack had damaged one of its desalination plants, signalling a widening assault on vital infrastructure across the region, reported Reuters.

As fighting ‌escalated on day nine of the US-Israeli campaign against Iran, Tehran moved closer to naming a new supreme leader after the killing of Ayatollah Ali Khamenei, with every indication suggesting his powerful son Mojtaba was emerging as the clear favourite.

Israel's military threatened to kill any replacement for Khamenei, while US President Donald Trump said the war might only end once Iran's military and rulers had been wiped out.

Thick, choking black smoke hung over Tehran on Sunday, residents said, after strikes on oil storage facilities, opens new tab had lit up the night sky with plumes of orange flame.

On the intense bombings in Tehran, the terrified residents described the horror to the BBC after several oil refineries in capital were targeted in Israeli strikes overnight.

A man in his 30s from Karaj, in the west of the Tehran province, said: "It started with a red light that lit up everything followed by a wave that jolted the door. Then the sky was lit again and a huge red cloud appeared."

A woman in her 20s said the city was covered in smoke."You can smell the burning," she said. "I can’t see the sun. There is a horrible smoke. It’s still there. I’m very tired."

Another woman in her 20s described opening the window "for a moment and it smelled like a pump station [burning]".

After the Karaj depot was hit, another man in his 20s described a "huge explosion and it was on fire for hours".

"By targeting fuel depots, the aggressors are releasing hazardous materials and toxic substances into the air, poisoning civilians, devastating the environment, and ​endangering lives on a massive scale," he wrote on X.

Israeli military spokesman Lieutenant Colonel Nadav Shoshani told reporters the depots were used to fuel Iran's war effort, including producing or storing ⁠propellant for ballistic missiles. "They are a legal military target," he said.

Shortly after the attack, Israeli Prime Minister Benjamin Netanyahu said his government would press on with the assault and strike Iran's rulers "without mercy".

"We have an organised plan with many surprises ​to destabilise the regime and enable change," he said in a video statement. "We have many more targets."

Trump told reporters aboard Air Force One that he was not interested in negotiating an end to the conflict that has sent energy prices skyward, hurt business ​and snarled global travel.

"At some point, I don't think there will be anybody left maybe to say, 'We surrender'," Trump said.

Iranian missiles hit Kuwait fuel tanks

The Kuwait army has said fuel tanks belonging to Kuwait International Airport were targeted in a drone attack, reported BBC.

"Fuel tanks belonging to Kuwait International Airport came under attack by drones, in a direct targeting of vital infrastructure," an official defence ministry spokesman said, according to a post by the Kuwaiti military on X.

The spokesperson said the country's armed forces had been dealing "with a wave of hostile drones that breached the country's airspace".

Meanwhile the governments of Saudi Arabia, Kuwait, the UAE and Bahrain have reported Iranian drone attacks in their countries on Saturday and early Sunday, with a huge fire engulfing a government office block in Kuwait.

Kuwait's interior ministry said two of its officers were killed "while performing duties", while the UAE said four migrant workers had died in Iranian attacks there so far.

Showing the intensity of the offensive, the UAE said air defence teams ​had knocked out 16 ballistic missiles and 113 drones fired towards the Gulf state on Sunday. One missile fell in the sea and four drones hit the country's territories, reported Reuters.

Bahrain said on Sunday that an Iranian drone attack had caused "material damage" to ​a desalination plant, though the country's electricity and water authority said the strike had not disrupted water supplies.

It was the first time an Arab country has said Iran targeted a desalination facility during the conflict. On Saturday, Iran said a U.S. attack had struck a ‌freshwater desalination plant ⁠on its Qeshm Island, disrupting water supplies in 30 villages, calling it "a dangerous move with grave consequences".