The existing 5,100-strong task force will be incorporated into a broader international mission, he announced.
French forces have been operating in Mali, Chad, Mauritania, Niger, and Burkina Faso to fight militants.
Last week, France paused operations in Mali following a military coup.
Militants linked to al Qaeda and the Islamic State (IS) group have strengthened their grip on the region, which has become a front line in the war against Islamist extremism.
It is also a major transit route for illegal drugs, weapons and jihadists.