Niger sent army helicopters to its western border with Mali on Wednesday to repel unidentified militants who crossed over to attack the town of Bani-Bangou, residents and military sources said.
Residents said the attackers had arrived on trucks and motorcycles during the afternoon before exchanging fire with Niger's security forces, causing locals to flee.
Niger's poorly policed west is close to Mali's desert north, where Islamist insurgents linked to al-Qaida have been hiding to regroup since a French-led military intervention ended their nine-month occupation of the region last year.
The clashes came on the eve of a third round of negotiations in Algeria between Mali's government and rebel armed groups from the north on the future of the troubled region.
Niger military sources said calm had returned by late Wednesday evening, adding that there were at least two serious injuries on their side.
"Clashes took place with our armed forces and there was gunfire, including heavy weapons fire," said a resident from a nearby village who asked not to be named.
At least 12 people — including nine members of Niger's security forces — were killed in attacks by unidentified insurgents in late October in the nearby western Tillaberi region.