Prison officials confirm two inmates are dead after an outbreak of violence at Tecumseh State Correctional Institution Thursday.

NDCS officials said the disturbance began around 1 p.m. after staff reported there was a fire in a yard connected to housing units. Approximately 40 inmates in one housing unit refused to return to their assigned cells. After officials said it became clear the incident was becoming unsafe, staff were directed to leave and secure the door to the rest of the housing unit and the prison was placed in lockdown status.

Officials said there were several altercations between inmates during this time. NDCS emergency response teams were activated. The violent incident inside the prison Thursday prompted officials to put Nebraska law enforcement on stand by.

At approximately 4:30 p.m. NDCS emergency response teams entered the affected area and secured all inmates. Officials said two inmates are confirmed dead and there are numerous inmates with non-life threatening injuries.

All day Thursday, the Department of Corrections insisted the incident was not a riot.

"In one of your press releases today you all made a point to say this was not a riot. Are you standing by that statement right now?” WOWT 6 News reporter Brandon Scott asked.

“I still would stand by that statement. This was not a riot,” Corrections Director Scott Frakes said.

“If two prisoners dead after violence and fires isn't a riot, what is?” Scott pressed.

“Hmm. I'm not going to try to define that off the top of my head at this point in time,” Frakes responded.

The names of the injured and deceased will not be released at this time. According to prison officials, NDCS are still notifying next-of-kin at this time.

All staff are safe and accounted for. The incident was isolated to one half of a housing unit and there was no risk to the public, according to prison officials.

"We’ve seen so many improvements over the last year and a half and I am proud of my team. This incident is a reminder that this is a dangerous business and we must remain vigilant as we keep people safe," Warden Hansen said.

The Nebraska State Patrol is on-site leading the criminal investigation.

This facility is the same one where a riot broke out in 2015, resulting in the deaths of two inmates, injuries to inmates and guards and millions of dollars in damage to the prison.