The bodies of 28 men killed by gunfire have been found in the northwestern Burkina Faso town of Nouna, prosecutors said on Monday.
An investigation has been launched into the killings which were discovered on December 30 and 31, prosecutors said in a statement that did not provide any details on the possible perpetrators or motive for the attacks.
One Nouna resident said she witnessed two armed men enter her home and kill her 74-year-old husband on December 30.
"They blindfolded him, took everything that was on him, forced him onto his knees and shot him with three bullets," said the woman, who asked not to be identified for fear of reprisals.
Jihadist insurgency
The West African country is battling a violent jihadist insurgency that has spread from neighboring Mali over the past decade. Thousands have been killed across the region, and millions forced to flee their homes.
On Monday, the Burkinabe civil society organization CISC blamed the Nouna attacks on armed civilians masquerading as members of the Homeland Defence Volunteers (VDP), a group that receives funds and training from the government to help fight the insurgents.