Bombers in the Nigerian town from which Boko Haram abducted scores of schoolgirls were men wearing hijabs with explosives strapped to their backs to look like babies, the military has said.

Some 17 civilians, a soldier and three bombers died, according to a community leader.

One bomber was discovered to be a man wearing a woman's dress when bodies were brought to Chibok hospital, a hospital worker confirmed.

Community leader Pogu Bitrus confirmed the toll, saying 17 civilians, one soldier and three suicide bombers died in multiple explosions on Wednesday, one at a checkpoint, the others at Chibok's open-air market.

Residents blamed Boko Haram extremists who kidnapped scores of schoolgirls in April 2014. Some 219 remain missing.