Islamic State group fighters could flee to Egypt or Tunisia after being flushed from their former Libyan stronghold of Sirte, French Defence Minister Jean-Yves Le Drian warned Monday.

"We should begin to look seriously at the question of the spread of the terrorists," Le Drian told a defence conference in Paris after Libyan pro-government forces recaptured most of Sirte from IS. "Indirectly this will pose new risks for Tunisia and Egypt."