Hezbollah, the Iran-backed group based in Lebanon, has launched dozens of rockets at the town of Beit Hillel in northern Israel, heightening tensions in the region. Footage posted on social media showed Israel’s Iron Dome air defence system intercepting the rockets, and there have been no reports of casualties.

The US embassy in Beirut has urged its citizens to leave Lebanon on “any ticket available”, amid soaring tensions in the Middle East. The advisory follows a similar warning from UK Foreign Secretary David Lammy, who said the regional situation “could deteriorate rapidly”.

Iran has vowed “severe” retaliation against Israel, which it blames for the death of Hamas chief Ismail Haniyeh in Tehran on Wednesday. His assassination came hours after Israel killed Hezbollah commander Fuad Shukr in Beirut.

It is feared that Hezbollah could play a heavy role in any such retaliation, which in turn could spark a serious Israeli response.

Jordan’s Foreign Ministry has also issued advice to its citizens, telling those in Lebanon to leave immediately and warning others not to travel there. Canada has warned its nationals to avoid travel to Israel, on top of existing advice against going to Lebanon, because the “situation can deteriorate further without warning” in the region.

The US embassy stated on Saturday that those who choose to stay in Lebanon should “prepare contingency plans” and be prepared to “shelter in place for an extended period of time”. It said that several airlines have suspended and cancelled flights, and many have sold out, but “commercial transportation options to leave Lebanon remain available”.

The Pentagon said it was deploying additional warships and fighter jets to the region to help defend Israel from possible attacks by Iran and its proxies.

The UK said it was sending extra military personnel, consular staff and border force officials to help with any evacuations - but urged UK citizens to leave Lebanon “while commercial flights are running”.

Two British military ships are already in the region and the Royal Air Force has put transport helicopters on standby.