More than 180 inmates in a medium-security prison in central Nigeria were at large after unidentified gunmen opened fire on the facility, the government said on Monday. The attack happened late on Sunday at the jail in the Tunga area of the Niger state capital, Minna. Guards were overpowered and inmates were able to escape. “Out of the 210 inmates that escaped from prison custody, 28 have been re-arrested while 182 are still at large,” Nigeria’s interior minister Abdurrahman Dambazau told reporters.

“We have identified some lapses… part of it is that the prison personnel on duty yesterday were inadequate,” he said after touring the prison. An investigation has begun but it was not immediately clear who or what was behind the incident.