France's defense minister says a U.N. peacekeeping force for restive northern Mali "hasn't been up to the task" amid a recent resurgence of insurgent attacks there.

Jean-Yves Le Drian tells RFI radio that his nation will step up its military activities in the Malian town of Tessalit as part of France's vast counterterrorism operation in the Sahel region.

In comments broadcast Monday, following his weekend return from a trip to west Africa, Le Drian said weapons flowing in from southern Libya have strengthened jihadist groups in northern Mali.

French forces largely expelled al-Qaida-linked insurgents from northern Mali last year, and some fled to Libya.

Asked about possible French action in Libya, Le Drian said simply "the question of southern Libya will come up — one day or another."