Burkina Faso authorities have said that bodies of 28 men killed by gunfire have been found in the northwestern town of Nouna.
They have now launched an investigation into the killings which were discovered last week, prosecutors said in a statement.
There are no details about the possible perpetrators or motive for the attacks.
The Burkinabe civil society organisation CISC on Monday however blamed the Nouna attacks on armed civilians masquerading as members of the Homeland Defence Volunteers (VDP).
Homeland Defence Volunteers is a group that allegedly receives funds and training from the government to help fight the insurgents.
Burkina Faso is battling a violent jihadist insurgency that has spread from neighbouring Mali over the past decade.
The crisis has killed thousands of people and displaced more than 2m in Burkina Faso and neighbouring countries.
The military seized power in Burkina Faso last January, promising an end to attacks but the violence still rages.
Source: Africafeeds.com