The massacre occurred Friday, a day after another deadly attack in the same area that killed 12 people.
“There have been 43 deaths in two days, all civilians, from the same community," tribal leader Sidigui Ag Hamadi told from the regional capital Menaka on Saturday.
"Our fighters are destroying their bases and wiping them out. They are targeting innocent civilians," he added.
Menaka governor Daouda Maiga said there were women, children and elderly people among the victims, but did not provide any figures.
The Tuareg rebel group called on the governments of Mali and Niger to take measures to ensure that "an immediate end is put to these abominable crimes" and stressed that it would "not give in to any intimidation."
The UN mission has 12,000 peacekeepers in the country. It has estimated that at least 180 civilians have been killed in Mali this year in at least 85 major violent incidents and armed confrontations.
