France has launched its first air strikes against the Islamic State group in Syria.

The French President Francois Hollande says the aim is to curb the militants' growing presence there.

The statement said: "Our country thus confirms its resolute commitment to fight against the terrorist threat represented by Daesh (Islamic State)".

"We will strike each time that our national security is at stake," the statement added.

France began making reconnaissance flights over Syria to gain intelligence earlier this month.