Two staff members at a southeastern Nebraska prison were assaulted Sunday. One of the staffers at the Tecumseh State Correctional Institution received injuries described as serious but not life threatening and required medical treatment.

The facility is secure and all staff are safe and accounted for according to an announcement by corrections officials.

During the incident Sunday morning, inmates in one housing unit gallery refused to return to their cells, but officials said they later did so without the need for force. The Nebraska Dept. of Correctional Services did not release the names of the two guards were assaulted.

Riots at the prison have claimed four lives in just over two years.

Officials at TSCI initially cancelled all visits for the day, but normal visiting schedules resumed by Sunday afternoon, except in Housing Unit 2a.