A spokesman for the U.N. peacekeeping mission in Mali says at least four peacekeepers are dead and six have been seriously wounded after their convoy hit a mine in the country's violent north.

Olivier Salgado said Tuesday that the group of Chadian peacekeepers was returning to the embattled town of Kidal when they struck a mine.

The deaths took place about 20 miles (30 kilometers) north of Kidal, which is home to a simmering separatist Tuareg rebel movement. Al-Qaida and other jihadist groups are also active in the area.

Northern Mali has seen a series of attacks on U.N. peacekeepers in recent weeks but Tuesday's attack was the largest in months.

The peacekeepers are trying to stabilize the country after a French-led war ousted the jihadists from power in 2013.