TECUMSEH, Neb. (AP) — Prison officials say three prison staffers at the Tecumseh State Correctional Institution were assaulted by inmates.

Department spokesman Andrew Nystrom said in a news release Monday evening that just before 4 p.m., an inmate hit a staff member escorting him inside a maximum-security housing unit.

The news release said that three other inmates started assaulting the staff member before two other staff members responded to the assault. Officials say the inmates were forcibly restrained by guards.

All three staff members were taken to a hospital with injuries not believed to be life-threatening.

The housing unit has been locked down, pending an investigation by the department.