At least 22 soldiers have been killed in Niger after unknown assailants attacked security forces guarding a camp for Malian refugees, according to Prime Minister Brigi Rafini.
The attack on Thursday targeted a camp in the village of Tassalit in Niger's Tahoua region, around 525km northeast of the capital, Niamey.
"We received information of an attack on the camp in Tassalit. For the moment we are told there are 22 dead, but that is not a total death toll," Rafini said in comments broadcast on state-run television TeleSahel.
"The death toll could increase."
The prime minister gave no further information concerning the identities of the attackers, or whether any civilians had been killed or wounded.
The camp's residents are Malians who fled to neighbouring Niger after armed groups, some with links to al-Qaeda, seized Mali's desert north in 2012.
A French-led military intervention has largely driven back the fighters, but violent attacks have continued across the region's Sahel band.
Niger's army is currently battling Boko Haram fighters who launch raids across its southern border from Nigeria while seeking to prevent an overflow of attacks from Mali.