The U.S. Penitentiary in Leavenworth was placed on lockdown following two fights in the same housing unit, a prison spokesman said in a news release.
The federal prison was placed on lockdown at about 3:50 p.m. Saturday as a precautionary measure, according to Public Information Officer Treavor Kroger.
He said the fights were isolated and quickly contained. A small number of inmates suffered minor injuries. No staff members were injured.
The investigation to determine the cause of the incidents was said to be ongoing. All programs, including visitation, have been suspended during the lockdown.