Four inmates were killed and 36 went missing on Wednesday when wardens shot at fleeing prisoners in a bid to thwart a jail break in southern Nigeria, police said.
"There was an attack on kitchen staff that were on duty at Ikot Ekpene prison in Akwa Ibom state by some prisoners," said state police spokesman Ogbajie Ogbajie in a statement.
"They seized an axe from a fellow inmate attached to the kitchen, inflicting a deep cut to the inmate's head in the process and immediately made for the rear entrance to the prison. They broke the door with the axe and engaged the staff that chased after them," he said.
"At the end of the scuffle, four of them that sustained gunshots lost their lives while seven were recaptured. Thirty-six are still at large and search parties have been activated to effect their recapture."
The police did not provide the number of inmates in the Ikot Ekpene prison at the time of the incident, but Nigeria's jails are usually overcrowded with prisoners living in poor conditions.
Local and international rights bodies have called on the authorities to improve the living conditions of inmates as well as giving prompt trials for suspects.