More than 20 soldiers were killed on Thursday when gunmen attacked a refugee camp for displaced Malians, Prime Minister Brigi Rafini said.

"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," said Rafini in an address broadcast on state-run television. "The death toll could increase."

The prime minister did not comment on who could have carried out the attack or what their motive may have been.

Tassalit is in the Tahaoua region, on the border with Mali and about 525 kilometers (326 miles) northeast of Niger's capital Niamey.

Those living in the camp had fled Mali after Islamist militants seized vast swaths of the country in 2012. A military campaign led by France last year mostly drove the insurgents back, but violence has seen a sharp uptick in recent months in the country's arid north.

Niger's small army is already stretched thing trying to fight off Boko Haram extremists, who are based in neighboring Nigeria but have launched attacks in several countries in the region. Niger also shares a border with Libya, and the possibility of so-called "Islamic State" militants spilling over the frontier there has also given Niamey cause to worry.

es/bw (AP, Reuters)