Around 170 people were "executed" in attacks on three villages in northern Burkina Faso a week ago, a regional prosecutor said in a statement seen on Sunday.
The attacks by unknown assailants were carried out on the villages of Komsilga, Nodin and Soro in the Yatenga province, the statement dated March 1 said, adding that an investigation had been launched.
The West African Sahel nation has been struggling to contain violent Islamist insurgencies linked to al Qaeda and Islamic State that have spread from neighbouring Mali over the past decade, killing thousands and displacing more than two million.