At least 200 members of the radical Boko Haram group were killed in Niger between Friday and Tuesday in confrontations with troops from both Niger and Chad.
"At least 200 Boko Haram members have been killed since the beginning of operations," Nigerien army spokesman Col. Moustapha Ledru told The Anadolu Agency.
He added that more Boko Haram militants were likely to be killed in ongoing operations against the militant group.
Troops from Niger are expected to join a multinational force tasked with fighting Boko Haram after the Nigerien parliament approved the move.
On Tuesday, Niger announced a state of emergency in Diffa, a city near the Nigerian border, due to repeated attacks by Boko Haram.
In a statement, the government said the move would allow security forces to raid homes in which Boko Haram "sleeper cells" were suspected of hiding.