The Burkina Faso military and allied militias have been accused of killing 100 civilians.
The incident is believed to have happened in March in the west of the country.
About 40% of Burkina Faso is currently under the control of jihadis linked to the Islamic State and Al-Qaeda.
According to Human Rights Watch, which has released a report on the alleged incident, over 100 ethnic Fulani were killed in an operation led by Burkinabe special forces. The Fulani are a pastoral ethnic group, who in the past have been accused of assisting jihadists in the country.
This most recent accusation is the latest in a string of alleged massacres by both sides in Burkina Faso.
Burkina Faso is currently under military rule, with the previous government (which also came to power through a coup) having been overthrown because of its failure to manage the Islamic insurgency in the country.
Image: Grok