NIAMEY, Niger — Military operations in Niger’s east have killed at least 500 of Nigeria’s Boko Haram Islamic extremists whose war has spilled over into neighboring countries, Niger’s police spokesman said Wednesday.

The provisional count of 513 since Feb. 8 does not take into account land and air operations launched Sunday jointly by Niger and Chad’s army in Nigeria, Capt. Adili Toro said.

Niger has also lost 24 soldiers in operations that have killed at least one civilian and wounded 38 soldiers, Toro said.

Recent offensives have marked a sharp escalation by African nations against Boko Haram nearly six years after the group began its insurrection. An African Union summit agreed on sending a force of 8,750 troops to fight Boko Haram.