Niger's police spokesman says that military operations in the country's east have killed at least 500 of Nigeria's Boko Haram Islamic extremists.

Capt. Adili Toro said Wednesday the provisional count of 513 killed since Feb. 8 does not take into account land and air operations launched Sunday by Niger and Chad's army in Nigeria.

He 24 Niger soldiers have been killed in operations that also wounded 38 soldiers.

Toro said a state of emergency would be extended by three months because more needs to be done.

Recent offensives have marked a sharp escalation by African nations against Boko Haram nearly six years after the group began its insurrection.

Boko Haram began launching attacks across the border into Cameroon earlier this year, and then struck in Niger and Chad.