Saudi Arabia has retaliated with hundreds of air strikes in the region.

The Houthis have also launched hundreds of drones and missiles at cities and infrastructure in south-western Saudi Arabia, including the capital city, Riyadh.

Prime Minister Andy Burnham has said the UK will provide “defensive air-to-air refuelling” support for Saudi Arabia, involving a single British aircraft, a Voyager, based out of RAF Akrotiri in Cyprus.

Burnham said the announcement followed a request from Saudi Arabia for “military support”, which he agreed to on the advice of Defence Secretary Wes Streeting and Foreign Secretary Ed Miliband.

A diplomatic source told AFP that France has pledged support as well, and says is ready to work on “securing” Saudi energy infrastructure via a “strictly defensive approach”.

Saudi Crown Prince Mohammed bin Salman has also requested military support from President Donald Trump, US media reported.

Trump has wavered for weeks over whether to act on a Saudi request for help in fighting the Houthis, the New York Times reported on Monday.

The US president had earlier told Fox News that he was in “deciding mode” as he considered options for the next steps in the war against Iran.

On Sunday, US embassies across the Middle East issued new security alerts as fighting between the Houthis and the Saudi-backed coalition in Yemen intensified.

The Houthis declare themselves to be part of the Iranian-led “axis of resistance” against Israel, the US and the wider West – along with armed group such as Hamas and Lebanon’s Hezbollah movement.

Although Iran has denied arming the Houthis in violation of a UN embargo, the UK and other Western powers have said their naval forces have repeatedly intercepted Iranian weapons shipments bound for Yemen during the civil war.

A panel of UN experts also concluded in 2024 that the Houthis had been transformed into a powerful military organisation due to the transfer of materiel, assistance and training from Iran’s Revolutionary Guards, Hezbollah and Iraqi specialists.

Yemen has been devastated by a civil war that began in 2014, when the Houthis ousted the government from the capital, Sanaa. The conflict escalated in 2015, after the Saudi-led coalition of Arab states intervened in an attempt to restore the government’s rule.

A four-year-old informal ceasefire began to unravel in July, when the Houthis announced a “maritime embargo” against Saudi Arabia and began missile and drone attacks on Saudi airports, oil facilities and tankers in the Red Sea.

The Houthis said they were retaliating for a Saudi blockade of ports and airports in their territory, as well as an air strike on Sanaa airport that they blamed on the kingdom.

Since taking control of Bab al-Mandab, they have said they pose no threat to international shipping but reiterated that they would continue to target vessels from Saudi Arabia.