The Feb. 27 incident at the males-only medium security Federal Correctional Institution Three Rivers (operated by Federal Bureau of Prisons) began about 8 p.m. when several inmates started fighting within the facility for unspecified reasons, reports show.
Four inmates sustained "non-life threatening injuries and were transported to a local hospital as a pre-cautionary measure," stated a news release issued by facility officials.
All four of those inmates have since returned to the institution, officials said.
Additionally, three staff members sustained minor injuries during this incident, reports show.
"The institution remains secure and has been placed on lockdown status," the release, issued Friday afternoon, shows. "All inmates were accounted for, and at no time was the public in danger. "
The cause of the fight remained under investigation Friday.