Gunmen shot dead 13 people and wounded seven others in a forest in Senegal’s southern Casamance region, the army said.
It was not clear who was responsible or what the motive for the attack on a group of civilians searching for firewood near Borofaye and close to the Guinea Bissau border, said army spokesman Abdoul Ndiaye.
The area is home to separatist rebels who in 1982 formed what is now one of Africa’s oldest rebellions in their search for independence from northern Senegal.
The Movement of Democratic Forces for Casamance (MFDC) is active in southern Senegal, separated from the more affluent north by Gambia.
The movement has been largely dormant since a 2014 ceasefire with many areas still off-limits because of land mines and arms stockpiles.
In his New Year address President Macky Sall called for dialogue with the rebels and a lasting peace.