Violence in the Sahel, a band of arid land that borders the south edge of the Sahara Desert, has intensified in recent years despite the presence of thousands of UN, regional and Western troops.
The violence, centred on the borderlands of Mali, Niger and Burkina Faso, has killed thousands of civilians and displaced millions since 2018.
On Monday, armed men killed 37 civilians, including 14 children, in an attack on a village in Niger. An attack in central Mali on Thursday killed 15 soldiers.
The Sahel was thrown into chaos by the takeover in 2012 of northern Mali by militants linked to al Qaeda.
France intervened the following year to push them back. But armed Islamists have regrouped and expanded their operations, making large areas of the Sahel ungovernable.