NAIROBI, Kenya — A US military spokesman says that the 80 personnel deployed to Chad to help find nearly 300 kidnapped Nigerian schoolgirls are from the Air Force and have already begun their mission.

Chuck Prichard, a spokesman at the US military’s Africa command in Germany, said Thursday that the 80 Air Force personnel were previously stationed in the United States, though he did not disclose where in the US.

President Obama told Congress in a letter Wednesday that the personnel will help with intelligence, surveillance and reconnaissance aircraft for missions over northern Nigeria.

The missing girls were kidnapped last month by the Islamic extremist group Boko Haram.