Six of the more than 1,800 inmates who escaped from the Owerri Custodial 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.

Channels Television had reported that some gunmen invaded the NCoS facility, as well as the State Police Command Headquarters very early in the morning, freeing hundreds of prisoners in the process.

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

He explained that the attackers, who stormed the facility at about 2:15am, gained entrance into the yard by using explosives to blast the administrative block.

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.

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.

While the gunmen attacked the Imo State Police Command Headquarters, they burnt almost all the vehicles parked at the command headquarters.

They 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.