The French military says at least three soldiers have been wounded in northern Mali after an explosion went off near an entrance to the volatile town of Kidal.

Hubert de Quievrecourt, a communications adviser with the French-led mission in Mali, said the three were wounded early Wednesday while on patrol in an armored vehicle.

The cause of the explosion was not immediately known, though jihadists operating in northern Mali have been known to place improvised explosive devices on roads.

Kidal is the epicenter of a secular separatist rebellion by Tuaregs, and the town also was under the control of radical jihadists for months last year.

Tensions are high in the north as Malians prepare to cast ballots Sunday in legislative elections.