More than 30 people were killed in desert clashes in northern Mali, the army and Tuareg rebels said, just days before the start of internationally-brokered peace talks.
Al-Qaida-linked Islamists took advantage of a Tuareg separatist uprising and occupied swaths of northern Mali in 2012 before being driven back last year by French troops.
The fighters scattered across the Sahara's mountains and sand dunes but have carried out a string of attacks on U.N. troops and Malian forces.
An army source said on Sunday that 37 people had been killed in clashes which began on Friday in the northern desert area between Gao and Kidal. The army blamed the violence on infighting between separatists.
Peace talks between Mali government officials and Tuareg rebels are due to start in Algeria on Wednesday, the first meeting since clashes in the Tuareg stronghold town of Kidal in May in which some 50 Malian soldiers were killed.
The army source said those killed in the most recent clashes were from the main Tuareg separatist group MNLA and a group of northern Malian Arabs called MAA.
However, MNLA spokesman Mohamed Ag Attaye said in a statement that 35 were killed from the Malian army and other “militias” and blamed government forces for starting the attack.
In past incidents, both sides have played down the casualties they sustained.
France dispatched troops to Mali last year to halt the advance by Islamists. The former colonial power currently has 1,700 troops in Mali and said on Sunday it was reorganizing its forces in Mali and surrounding countries into a single regional body.
“It's a regional operation to ensure the security of the area and prevent jihadist groups from emerging again,” French Defense Minister Jean-Yves Le Drian said on Europe 1 radio.
The United Nations has also deployed a peacekeeping force in Mali which operates separately from French troops.
U.N. peacekeeping chief Herve Ladsous said on Friday he was “concerned by certain armed groups' violation of the cease-fire agreements signed with Bamako on May 23.”
France, as well as Mali's northern neighbor Algeria and the West Africa regional bloc ECOWAS are pushing warring sides to hold talks that could end decades of Tuareg uprisings in Mali's desert north.
In addition to deep distrust between the armed groups and Bamako, tensions between the separatists is a challenge for mediators. On several occasions, disagreements have led to open conflict between them.
The 2012 uprising led to a military coup in the capital and the occupation of the northern half of the country by Islamist militants who had allied with the rebels.
Mali's separatist movements are demanding greater autonomy for northern Mali, which they term Azawad.