Niger's military regime said Tuesday that six soldiers and 31 "terrorists" had been killed in fighting in a restive region plagued by insurgents linked with Al-Qaeda and the Islamic State group.

Clashes between armed forces and "terrorist elements" broke out in the western Tillaberi region near Burkina Faso between Sunday and Monday, the defence ministry said.

According to AFP, eighteen soldiers were also injured, it added in a statement.

Tillaberi is in the vast and unstable "three borders" region between Niger, Mali and Burkina Faso, where jihadist insurgents have carried out attacks for years.

The latest fighting, which erupted in an area northwest of the town of Tera, follows several other deadly attacks in the region in recent weeks.

At the start of the month, Niger held three days of national mourning after 29 soldiers were killed in a suspected jihadist attack, the deadliest since the military took power in July.

Niger is battling two jihadist insurgencies -- a spillover in its southeast from a long-running conflict in neighbouring Nigeria, and an offensive in the west by militants crossing from Mali and Burkina Faso.

When military leaders overthrew democratically elected president Mohamed Bazoum on July 26, they cited the deterioration of the security situation in the country as justification.