DAKAR: An attack by armed men in western Niger killed 12 soldiers, the army said on Saturday, in a border area that has long been a hotbed of extremist violence.
The "surprise offensive" was launched on Friday against a military unit near the village of Sakoira near the border with Mali and Burkina Faso, the army said in a statement.
It described the assailants as 'terrorists' but did not say what group was responsible.
The tri-border area has long been a site of extremist violence.
Last month, an attack by a jihadi group on a village in the region killed 44 civilians.
The army blamed that attack on the Islamic State in the Great Sahara, or EIGS.
Niger, along with its neighbours Burkina Faso and Mali, has for over a decade battled an insurgency fought by jihadi groups, including some allied with al-Qaida and the Islamic State group.
Following military coups in all three nations in recent years, the ruling juntas have expelled French forces and turned to Russia's mercenary units for security assistance.
The three countries have vowed to strengthen their cooperation by establishing a new security alliance, the Alliance of Sahel States.
But the security situation in the Sahel, a vast region on the fringes of the Sahara Desert, has significantly worsened since the juntas took power, analysts say, with a record number of attacks and civilians killed both by Islamic militants and government forces.