Authorities say at least 35 civilians were killed when a bomb exploded near a vehicle convoy in northern Burkina Faso, where jihadist rebels are active.
Several other people were injured in the blast on the road between Djibo and Bourzanga.
Convoys escorted by the army of Burkina Faso are used to deliver supplies to towns cut off by the jihadists.
Since the military seized power in Burkina Faso in January, civilian casualties and jihadist attacks have increased.
Burkina Faso, which is one of the poorest countries in the world, has been grappling with a jihadist insurgency that swept in from neighbouring Mali in 2015.
More than 2,000 people have died and some 1.9 million forced to leave their homes.