The statement says the land and air raids began on Dec. 28, with more than 200 extremists killed in airstrikes.
Nigeria in November held an urgent meeting with neighbors about what it called an extremist resurgence fueled by the new use of drones.
Niger's statement says no troops were killed in the raids in its east. It notes that Nigeria "suffered a string of recent attacks on its military bases" and that the extremists had been reinvigorated.
Niger's defense minister last month said he feared Boko Haram would launch renewed attacks from January, when the Komadougou-Yobe river which usually prevents border incursions begins to recede.