Prime Minister Sir Keir Starmer and US President Donald Trump have agreed the mounting conflict between Iran and Israel should be resolved by “diplomacy and dialogue”.
The two leaders spoke on Friday evening, as western nations began a diplomatic flurry to calm the burgeoning conflict, which started with early morning Israeli strikes on Iranian nuclear bases.
Sir Keir earlier urged his Israeli counterpart Benjamin Netanyahu to de-escalate and work towards a “diplomatic resolution”.
David Lammy, the Foreign Secretary, meanwhile warned the Middle East is facing a “moment of grave peril”, after he spoke to Iran’s foreign minister and called for calm.
Earlier calls from the PM, as well as France’s Emmanuel Macron and Germany’s Friedrich Merz, for restraint appeared fruitless, as a fresh wave of strikes hit Tehran and other targets across Iran on Friday evening.
Ayatollah Ali Khamenei, Iran’s supreme leader, vowed revenge, and his country launched hundreds of ballistic missiles at Israel in a retaliatory attack.
Air raid sirens were sounded across Israel and its citizens were ordered to move into bomb shelters, while plumes of smoke could be seen rising in central Tel Aviv.
In London, the Prime Minister convened a Cobra meeting of high level ministers and officials to discuss the situation in the Middle East.
Warren Stephens, the US ambassador to the UK, was also seen outside the Cabinet Office in Whitehall after the meeting on Friday afternoon.
A Downing Street spokeswoman said Sir Keir and Mr Trump “discussed the military action in the Middle East overnight and agreed on the importance of diplomacy and dialogue” when they spoke on the phone.
She added: “Updating on his conversations with partners today, the Prime Minister reiterated the UK’s grave concerns about Iran’s nuclear programmes.
“The leaders looked forward to speaking again at the G7 in Canada next week.”
Both the UK and the US have insisted they were not involved in the Israeli strikes and that Israel acted unilaterally.
Foreign Secretary Mr Lammy would not say whether the Government had been forewarned of the action.
Tzipi Hotovely, Israel’s ambassador to the UK told Sky News the first time the her country discussed the strikes with the UK was at midday on Friday.
She also told the broadcaster: “The aim is to make sure Iran won’t have nuclear capabilities. This is why all our targets are military targets. This is why we’re attacking the nuclear sites.
“This is not a plan that was created in one night. This is a plan being created in many years from understanding the levels of danger.”
Among the sites hit by Israel’s strikes are several of Iran’s main nuclear sites, as well as missile factories.
Hossein Salami, the leader of Iran’s Islamic Revolutionary Guard Corps, was also reportedly killed in the initial attacks.
Mr Netanyahu addressed people of Iran in a video on Friday night, insisting his quarrel was with the Iranian ruling regime.
“In the past 24 hours, we have taken out top military commanders, senior nuclear scientists, the Islamic regime’s most significant enrichment facility and a large portion of its ballistic missile arsenal,” he said.
“More is on the way” in Israel’s operation, the Israeli PM added.
Tensions between Israel, the US and Iran have escalated in recent weeks, amid negotiations over the Iran nuclear deal, which is aimed at preventing the country from developing nuclear weapons.
Mr Trump had suggested some sort of attack by America or the Israelis could happen if negotiators failed to reach a deal over the advancing nuclear programme.