A military unit and VDP volunteer auxiliaries were ambushed on Saturday between Sakoani and Sampieri in Tapoa province, bordering Niger and Benin, an army statement said.

"The fighting unfortunately cost the lives of two soldiers and two VDP," it added.

However, a security source told AFP the death toll was four soldiers and two volunteers.

A VDP official confirmed two dead from the volunteer ranks with "some still missing".

Another security source said the jihadists also suffered losses, without giving a figure for the dead.

Lieutenant-Colonel Paul-Henri Sandaogo Damiba seized power in a January coup, ousting Burkina's elected leader and promising to rein in the jihadists.

But the violence has raged on as in neighbouring countries stoked by insurgents affiliated to Al-Qaeda and the Islamic State group.

Thousands have died and some two million been displaced by the fighting in landlocked Burkina since 2015.