Reports from Burkina Faso say around 40 people were killed in two separate attacks by alleged jihadists at the weekend.
Around 20 army volunteers died near Bourasso close to the Malian border on Saturday.
A similar number of people died in another attack in the same area on Sunday.
Sources say that following Saturday's violence, tens of insurgents were "neutralised" in an airborne operation by government forces.
Burkina Faso's Prime Minister Apollinaire Kyélem de Tambèla told parliament that his government would never negotiate with the jihadists.