The Movement for Unity and Jihad in West Africa (MUJWA) was responsible for killing 31 Tuaregs in an attack on Friday near the town of Tamkoutat in northern Mali, the minister for interior security said on Sunday.
General Sada Samaka, who visited the site of the attack accompanied by Malian army officers, told Malian national television that the killings took place around 2:00 p.m. local time (1400 GMT) on Friday some 12 km (7.5 miles) outside Tamkoutat.
"The travellers aboard two vehicles fell into an ambush laid by the terrorists of the MUJWA," said the minister. He said a young girl and a woman were amongst those killed.
Initial reports had attributed the killings to the settling of scores between Peul and Tuareg ethnic groups. The MUJWA has not claimed the attack.
A French-led offensive in January 2013 drove out Islamist militants who had seized control of northern Mali. Pockets of fighters loyal to armed Islamist groups, including the MUJWA and Al-Qaeda's local branch AQIM, continue to operate in the desert region, carrying out periodic attacks.
France is winding down its troop presence but has said it will keep more than 1,000 soldiers in Mali to counter a regional armed Islamist threat.
Malian authorities said 25 people were killed in the ambush and four wounded. The attackers later killed six other people in two camps and wounded three more.
President Ibrahim Boubacar Keita's government stepped up security in the southern capital Bamako following the attack.
Security sources said the killings appeared to signal a move by the Islamist group away from suicide attacks on military installations towards targeting the local civilian population.