Two suspected jihadists have been arrested over the Solhan attack in the north-eastern region of Burkina Faso on 4 June in which more than 130 people were killed.
The prosecutor announced the arrest of two suspects, aged 28, in a statement.
Both claim to belong to the Mouhadine group, meaning “People in Solidarity”, which is thought to be affiliated to al-Qaeda.
It is divided into several sub-groups based in Burkina Faso and has led incursions into Niger and Benin.
The prosecutor said the the group was responsible for previous attacks in Solhan, Sebba, Boundoré and Koholoko on the Niger border.
The prosecutor has requested the opening of a judicial investigation into the two suspects on a number of terrorism-related charges.
The attack on the village of Solhan, which took place at an artisanal mining site, is considered to be the deadliest attack in Burkina Faso since April 2015.
It has caused discontent and criticism about the ability of the defence and security forces to contain jihadist violence in the country.
On Sunday evening, in a radio and television message, President Roch Marc Christian Kaboré promised to strengthen the operational capacity of troops on the ground.