Donald Trump has approved plans to attack Iran, but has not made a final decision on whether to strike the country, the BBC's US partner CBS reports.

The US president held off from initiating strikes in case Iran agreed to abandon its nuclear programme, a senior intelligence source told CBS. Trump is reportedly considering a US strike on Fordo, an underground uranium enrichment facility in Iran.

Iran's Supreme Leader Ayatollah Ali Khamenei on Wednesday rejected Trump's demand for unconditional surrender, as the US president said his patience had run out.

On Wednesday, Trump said, "I may do it, I may not do it", when asked a question about US involvement in Iran.

Khamenei rebuked Trump in Wednesday's recorded speech, saying that "any US military intervention" would be costly and added: "The Iranian nation will not surrender."

Trump brushed off the rejection, saying "good luck", but again declined to disclose his plans. "I mean, nobody knows what I'm going to do," he said.

"Unconditional surrender – that means I've had it."

The news of Trump backing strike plans was first reported by the Wall Street Journal.

Israel's military launched more attacks on Iran, hitting missile sites and nuclear facilities. Iran said it had fired hypersonic missiles in response. No serious damage was reported in Israel.

It was Khamenei's first appearance since Israel launched what it described as pre-emptive strikes on Friday.

Iran's mission to the United Nations mocked Trump in posts on X: "Iran does NOT negotiate under duress, shall NOT accept peace under duress, and certainly NOT with a has-been warmonger clinging to relevance.

"No Iranian official has ever asked to grovel at the gates of the White House," it added.

"The only thing more despicable than his lies is his cowardly threat to 'take out' Iran's supreme leader."

The war of words came as Iranians continued to jam roads out of the capital Tehran, a city of 10 million people, seeking sanctuary from Israeli attacks.

Benjamin Netanyahu, Israel's prime minister, said in a video on Wednesday that his country's forces were "progressing step by step" towards eliminating threats posed by Iran's nuclear sites and ballistic missile arsenal.

"We control the skies over Tehran. We are striking with tremendous force at the regime of the ayatollahs. We are hitting the nuclear sites, the missiles, the headquarters, the symbols of the regime," he said.

Pete Hegseth, Trump's defence secretary, told a Senate committee that the Pentagon was prepared to execute any order given by Trump.

His comments came amid a build-up of American forces in the Middle East. A carrier strike group led by the USS Nimitz aircraft carrier was steaming from south-east Asia to join another strike group led by the USS Carl Vinson, already in the Gulf.

Various air assets including refuelling tankers were also seen on flight trackers moving from Europe, with reports of F-22 and F-35 strike aircraft following.

The US State Department said Secretary of State Marco Rubio would meet UK Foreign Secretary David Lammy in Washington DC on Thursday, for talks expected to focus on Iran.

The BBC understands that, so far, the US has not made a formal request to use the UK's military bases in Diego Garcia or Cyprus to conduct strikes against Iran.

Normally, the US would first inform its ally if it intended to conduct offensive operations from those bases. A British source said it was believed "all options" were on the table in Washington but there was no complete picture of America's intent.

The US embassy in Jerusalem on Wednesday issued an evacuation plan for American citizens currently in Israel. It was unclear how many Americans were seeking to leave Israel or whether the US military would assist with the evacuation flights.

Since it launched its attack on Friday, Israel's strikes on Iran have killed 585 people, according to Washington DC-based group Human Rights Activists, which said that 239 were civilians and 126 were security personnel.

In retaliation, Iran has fired around 400 missiles at Israel, killing 24 people, all of them civilians, according to Israeli authorities.

Meanwhile, Iranian state TV warned viewers to ignore an "irrelevant" clip calling for the public to "rise up" against the regime, after an apparent hack of its satellite feed.

"If you notice irrelevant messages while watching TV, it is due to the enemy jamming satellite signals," state TV said.

Hackers apparently broke in and broadcast a video that accused the Iranian establishment of "failing" its own people, called on viewers to "take control of your future". It featured several clips of mass protests against the regime in 2022.