Burkina Faso's army said on Wednesday that it accidentally killed civilians during a counter-terrorist operation in the country's southeast earlier this week.

The West African country has been battling an insurgency by Islamist militant groups, some linked to al Qaeda and Islamic State, which control large swathes of territory and wage frequent attacks.

"During operations which made it possible to neutralize several dozen terrorists, the strikes unfortunately caused collateral victims within the civilian population," the army said in a statement.

It did not say how many civilians were killed. The victims were hit by projectiles in the zone between Kompienga and Pognoa, near the border with Togo, on Monday, it said.

Togo, which has been contending with the spillover of militancy from Burkina Faso, accidentally killed seven civilians in an air strike last month near the same border.