"A terrorist attack targeted passenger vehicles on Friday June 13, killing nine civilians," a teachers' union said in a statement. One of its members had been among the dead, it added.

The union said the attack happened around 10:00 am (0900 GMT) on the road linking Makalondi and Torodi near the border with Burkina Faso.

A second teacher was wounded and evacuated to Niamey for treatment, said the union, denouncing the attack as a "despicable act".

A Torodi resident confirmed the incident, saying there had been "civilian casualties".

Torodi and Makalondi lie less than 100 kilometres (60 miles) from Niamey, where the army says it is dealing with "persistent terrorist threats" including "improvised explosive devices" on roads.

The towns fall within Tillaberi region's "three borders" zone -- shared by Niger, Burkina Faso and Mali -- a hotspot for attacks by Islamic State and Al-Qaeda affiliates.

Niger's army said Saturday evening it had "neutralised (killed) 13 terrorists" between June 8 and 14 during operations at illegal gold mining sites in Teguey, a commune in the Tillaberi region.

It also said it had killed around 30 members of "criminal cells in training" in the Dosso area (southwest), near the Nigerian border.

Like its neighbours Burkina Faso and Mali, Niger is ruled by a military junta and faces escalating jihadist attacks.

The three countries have formed a confederation called the Alliance of Sahel States (AES). Earlier this year they announced the creation of a joint 5,000-strong force, joint military operations.