The military base in the city of Tessalit is one of several former UN bases that the Malian army and its Russian allies have lost control of.
A source within an armed separatist force told AFP on Friday that the army "just gave up, like they did in Kidal."
Last weekend, a motley coalition of jihadist and separatist nomadic groups launched an unusually large-scale assault on the military junta's rule. The large city of Kidal was quickly captured, as were several other towns in the north.
