France has called on its citizens to leave Iran “immediately” amid fears the Islamic Republic is preparing to attack Israel in response to the assassination of the leader of Hamas.

The foreign ministry called on all visiting French nationals still in Iran to leave “as soon as possible” owing to the “increased risk of a military escalation in the region”.

Gérald Darmanin, France’s foreign minister, has also called for increased security for Jewish communities in France because of the “very high level of tension”.

This includes the “many Israeli nationals” attending the Olympic Games, he said, after Hamas declared a “day of anger” on Friday, BFMTV reported.

Israel was preparing for a possible attack on Friday after Iran promised to “punish” Jerusalem for the killing of Ismail Haniyeh, who The Telegraph learned was killed by a remote-controlled explosive device in his guesthouse in Tehran.

Israeli ministers have been given satellite phones in preparation for an attack that could strike the country’s communication system, Israeli media Ynet reported.

Lebanon’s Hezbollah was also preparing for a wider escalation to ignite, moving its military equipment into central Beirut, according to Saudi news outlet Al-Hadath.

An official within Iran’s Revolutionary Guards told The Telegraph that Iran is considering targeting Tel Aviv in revenge for Haniyeh’s assassination in Tehran.

“Top commanders were awake all night evaluating the options. Now that Mr Haniyeh’s funeral has concluded, they are discussing practical responses,” said the Islamic Revolutionary Guard Corps (IRGC) official who attended the funeral on Thursday.

The White House said that Joe Biden discussed “efforts to support Israel’s defense against threats,” in a phone call with Benjamin Netanyahu, “including against ballistic missiles and drones, to include new defensive US military deployments.”

The US is also preparing to send additional combat aircraft to the region to protect both Israel and American troops from Iran and its proxies, US officials told The New York Times.

Numerous airlines have cancelled their flights to Lebanon and Israel in recent days following the assassination of Haniyeh as well as top Hezbollah commander Fu’ad Shukr in Beirut.

Air India announced on Friday that it was cancelling all flights to and from Israel until August 8 while Polish airline LOT cancelled eight flights to Lebanon and Israel, according to PAP news agency.

John Healey, Britain’s Defense Secretary, met with his Israeli counterpart Yoav Gallant in Israel on Friday, discussing the IDF’s “readiness and capabilities to defend Israel on all fronts”

Mr Gallant said he emphasized the importance of “establishing a coalition in Israel’s defense against Iran and its proxies.”

Israeli airstrikes against Hezbollah continued on Friday, with a drone targeting one of the militant group’s members who attempted to launch rockets toward Israel.