LINCOLN, Neb. (AP) — Two fights among inmates prompted officials to order a lockdown of the Nebraska State Penitentiary in Lincoln.

The incidents happened Tuesday evening, with the separate fights each involving two people.

Department of Correctional Services spokeswoman Dawn-Renee Smith says officers ultimately restrained five inmates and removed them from a penitentiary yard.

During the incident, four inmates refused to return to their cells.

Smith says the prison instituted a modified lockdown for 40 minutes and had returned to normal operations by Wednesday morning.

Nebraska corrections officials have dealt with numerous violent incidents since May 2015, including prisoner deaths and assaults on officers.

The department didn’t release information about the Tuesday fights until questioned by the Journal Star. Smith says the agency didn’t issue a new release because no staff members were seriously injured.

___