Six of the more than 1,800 inmates who escaped from the Owerri Correctional Centre in Imo State have voluntarily returned to the facility, authorities have said.

The Public Relations Officer of the Nigerian Correctional Service (NCoS), Francis Enobore, confirmed this in a statement on Monday.

He disclosed that during the incident at the correctional facility in the state capital, 35 other inmates refused to escape from custody.

Hours after the attack, Enobore confirmed that the gunmen forcefully released a total of 1,844 inmates from custody.

They were reported to have invaded the correctional centre in their large number in several Hilux pick-up vans and Sienna Buses, armed with sophisticated weapons, and immediately engaged the security personnel on duty in a fierce gun battle after which they eventually detonated the explosives to gain entrance.

Condemning the incident, the Acting Controller-General of Corrections, John Mrabure, ordered a comprehensive investigation into the attack.

He also directed the commencement of search and recovery operations, in collaboration with other security organisations, to recapture the fleeing inmates.

Mrabure equally directed all officers attached to custodial facilities across the country to remain vigilant at this trying moment.

He appealed to the residents of Imo and others to help with useful intelligence that would facilitate the recovery effort.

During the attack, one person suspected to be a fleeing inmate was hit by a bullet while carrying his travel bag. His lifeless body was visibly seen on the ground in front of the correctional centre.

The gunmen who also attacked the Imo State Police Command Headquarters, were said to have chanted solidarity songs at the Government House Roundabout for about 30 minutes before the attacks on the correctional service and police facilities, burning almost all the vehicles parked at the command headquarters.