On Thursday, security and local sources gave a provisional toll of seven soldiers killed in an assault on a military unit, while a separate attack on a bus left one civilian dead.

But in a statement released overnight, the military chief of staff said that 11 troops had been killed.

"A complex attack -- shells fired, followed by direct fire on the base" in Madjoari in the Kompienga province, it said in a statement.

"Eleven soldiers lost their lives... (and) at least 20" wounded, it said.

Army warplanes helped to "neutralise at least 15 terrorists who were trying to escape after the attack," it said.

On Saturday, around 40 people -- many of them civilian volunteers with the army -- were killed in three suspected jihadist attacks in the same regions.

Burkina Faso has been battered by jihadist raids since 2015, with movements linked to Al-Qaeda and the Islamic State group.

More than 2,000 people have been killed and 1.8 million displaced.

The new head of state, Lieutenant-Colonel Paul-Henri Sandaogo Damiba, says he has made the security crisis his "priority".

Damiba overthrew elected president Roch Marc Christian Kabore in January, accusing him of being ineffective in the face of jihadist violence.

After a relative lull when Damiba took power, a surge in attacks has claimed almost 200 lives.

In early April, Damiba announced the creation of local committees to try to engage with jihadist groups and curb the violence.