Amnesty International on Wednesday accused armies in Africa's sprawling Sahel region of unlawfully killing or forcibly disappearing some 200 people this year, adding that many incidents could amount to war crimes.
The rights monitor said that the militaries of Mali, Burkina Faso and Niger slew at least 57 people and forcibly disappeared at least 142 others between February and April.
Much of the semi-desert central Sahel region is plagued by Islamist militants, who first emerged in Mali in 2012, before spreading to Burkina Faso and Niger.
Despite the presence of thousands of French and United Nations troops in the region, Sahel states have struggled to quell the jihadist insurgency.
Thousands of soldiers and civilians have died in the conflict to date, and many more have had to flee their homes.
Amnesty's report comes at a time of mounting concern over alleged human rights abuses committed by authorities in the region.
On Saturday, Mali vowed to investigate claims that its own troops had killed some 30 villagers in the volatile centre of the country.
The United Nations Security Council also debated allegations of human rights violations by Sahel armies on Friday.
According to Amnesty, military abuses have occurred as governments are ramping up their operations against jihadists.
"The deliberate killings of unarmed civilians by security forces in Mali and Burkina Faso may constitute war crimes under international law and should be thoroughly investigated," it said.
"These violations were usually perpetrated following losses of the security forces against armed groups".
Amnesty recorded allegations of forced disappearances by Nigerien armed forces, but of no extrajudicial killings.
Wednesday's report was based on 33 interviews, and on photographic evidence of dead victims and mass graves.
