Islamist forces in northern Mali vowed on Monday to retaliate for France’s military campaign against them. The leader of the Movement for Oneness and Jihad in West Africa, an al Qaeda offshoot, said, “France has attacked Islam. We will strike at the heart of France.” France launched the offensive alongside the Malian Army on Friday to stop the Islamist insurgents who had threatened to advance on the capital of Bamako. A town in central Mali, however, had fallen as of Monday morning. The offensive killed 60 Islamists in the city of Gao alone on Sunday.