Gunmen killed at least five people near Mali's troubled northeastern border with Niger, several sources said on Thursday.
A vehicle travelling from Indelimane to a market in Menaka on Wednesday "was attacked by armed men", a local elected official told AFP on the condition of anonymity.
Five civilian passengers were killed by "assassins who then went to a camp to kill other Tuareg civilians", he added. Other sources reported a higher toll.
The attack was confirmed by a Malian security source who said that "criminals murdered six civilians on Wednesday between Indelimane and Menaka", and reports on the Facebook page for the pro-government group GATIA said "armed bandits" attacked a vehicle.
GATIA - the French acronym for the Imghad and Allies Tuareg Self-Defence Force - said "six civilians were summarily executed", then "two other civilians were killed in a camp near the scene of the attack".
The unrest in the former French colony stems from a 2012 Tuareg separatist uprising against the state, which was exploited by jihadists in order to take over key cities in the north.
Wednesday's violence came shortly after a visit to Menaka by Malian Prime Minister Soumeylou Boubeye Maiga following a wave of deaths in recent months.
Since the end of April, about 60 Tuareg, including children and elderly people, have been killed in camps south of Menaka, an area where jihadists claiming allegiance to the Islamic State (ISIS) group operate.
Residents in the region consider the killings as reprisal attacks by the jihadists who have suffered heavy casualties in recent fighting with the French force Barkhane and the Malian army, often supported by the Azawad Movement for the Salvation (MSA) and GATIA.