The explosion happened Saturday in the northern Tone prefecture near the border with Burkina Faso, where militants linked to the Islamic State group and Al-Qaeda are active.

Togo's troops are deployed in the area to try and contain a spillover of the threat towards coastal West Africa.

The army said Sunday it had opened an investigation "to determine the circumstances of this explosion and identify the perpetrators".

On Thursday, Togo's armed forces chief of staff General Dadja Maganawe concluded an aircraft had wrongly targeted the civilians in the village of Margba, in Tone prefecture.

General Maganawe said in a statement the army had previously received "intelligence" indicating a threat of "infiltration by armed gangs wanting to conduct terrorist attacks" against local communities.

"Because of the imminent danger," he said the commander leading an operation code-named Koundjoare "reinforced surveillance as well as ground and aerial control in the area".

"It was during those operations that an aircraft patrolling at night unfortunately targeted a group of people it had mistakenly identified as jihadists on the move," Maganawe said.

"The Togolese armed forces express their profound regret in the face of this tragedy, and renew their sincere condolences to the families of those affected, and once more, wishes a prompt recovery to those injured."

He added that "everything possible" would be done "to prevent this sort of tragedy from happening again".

Togo last month declared a state of emergency in its northern prefectures over the threat of Islamist militant attacks.

Eight Togolese soldiers were killed in May in an attack in the region.