Armed men stormed a Nigerian prison on Monday, freeing multiple inmates before setting the correctional facility ablaze, Nigerian police said.

The gunmen also destroyed the State Police Command headquarters in Owerri, the capital city of the state, and burnt down almost 50 vehicles parked at the main office, a witness told Anadolu Agency.

The Nigerian Correctional Service, a government agency of Nigeria that operates prisons, confirmed the attack but declined to give casualty figures.

James Madugba, a spokesperson for the prison department, told reporters the authorities were still trying to get the accurate data of inmates who escaped and the level of devastation caused.

"There was an attack on the Nigerian Correctional Centre very early this morning around 2:15 a.m. (1:15 GMT) and some of the vehicles were burnt. Fire service came to contain the fire. We are yet to confirm exactly what happened," he said.

Confirming a firefight between police and gunmen, he said details will be shared soon.

No group has so far claimed responsibility for the attack.