Strikes on the strategic Malian town of Kidal on Tuesday killed at least six people, including children, witnesses and residents said, attributing the strikes to Mali's army.
"There were several strikes this morning," a health worker said on condition of anonymity. "There were six deaths including three children."
Other witnesses reported a higher death toll in the northern town, a stronghold of Tuareg-dominated rebel groups and a major sovereignty issue for Mali's junta-led government.
Some witnesses described air strikes while one cited drones, but few details were provided.
Almou Ag Mohamed, a spokesman for the Coordination of Azawad Movements (CMA), an alliance of separatist groups dominated by Tuareg fighters, told AFP there had been 12 deaths, including four children, in three separate strikes.
At least one of the strikes hit a camp recently vacated by the UN stabilisation mission.
The rebels control the town of Kidal.
Though they had signed a peace agreement with the government in 2015, they have recently resumed hostilities.
The Kidal region has long been a centre of insubordination and a launching point for independence rebellions, an old source of irritation for governments in the capital Bamako.
The army suffered humiliating defeats in the region between 2012 and 2014.