An official in northern Mali says assailants have attacked soldiers escorting a humanitarian convoy, killing two and wounding two others.

It wasn't immediately clear who was behind the attack, although groups with links to al-Qaida are active in the area.

Moussa Maiga, a civil servant in the town of Timbuktu, said the violence took place early Friday as the soldiers guarded a humanitarian mission aimed at helping refugees returning to the area from neighboring Mauritania.

Many Malians from the north fled during the 2012 reign of Islamic extremists groups. While a French-led operation forced them from power the following year, violent attacks on peacekeepers have been growing.

Friday's attack was also confirmed by Lt. Col. Diarran Kone, an adviser to Mali's defense minister.