Burkina Faso's army say soldiers have killed an extremist leader and five other militants in Nahouri Province.

In a statement released on Friday by the armed forces' chief of staff, the soldiers were conducting an operation in the region to dismantle the militant group that operates in the country's south-central region.

It identified the leader as Abdoul Hadi, who is known to have helped extremist group Ansarul Islam establish a presence in the area.

The statement also said the army had seized a large cache of weapons in the raid.

Extremist groups have increased attacks in the West African nation in recent months, forcing nearly half a million people to flee their homes.

The latest development comes after the U.S. Embassy in Ouagadougou earlier this week ordered the departure of family members of embassy employees under the age of 21 from the country due to the deteriorating security situation.

The embassy said there was no specific threat, but the security situation in the country had reached a point where it was no longer "appropriate" for children to remain with the embassy community.