A Nigerian Air Force fighter jet on a mission against Boko Haram extremists mistakenly bombed a refugee camp Tuesday, killing more than 100 refugees and wounding aid workers, a Borno state official said.

A Red Cross worker said 20 volunteers with the aid group had been killed.

The state government official, who was helping to coordinate the evacuation of wounded from the remote area by helicopters, spoke to The Associated Press on condition of anonymity because he was not authorised to speak to reporters.

Military commander Maj. Gen. Lucky Irabor confirmed the accidental bombardment in northeast Rann, near the border with Cameroon.

This is believed to be the first time Nigeria's military has admitted to making such a mistake.