"Due to the increased risk of a military escalation in the region, visiting French nationals still in Iran are invited to leave as soon as possible," the foreign ministry said.

The killing of Hamas political chief Ismail Haniyeh in a pre-dawn attack on Wednesday in Tehran has deepened fears of a regional war.

Tehran, as well as Hamas and Lebanese Hezbollah movements, have blamed Israel, which has not commented.

It has however claimed responsibility for the killing just hours earlier of senior Hezbollah military commander Fuad Shukr in Beirut's southern suburbs.

Hundreds of people gathered at a mosque in Qatar on Friday to bid farewell to the slain leader.