A "disturbance" at an Oklahoma prison Saturday afternoon left four inmates dead and several more hospitalized, officials said Sunday.
The brawl, at Cimarron Correctional Facility, started and ended at around 5 p.m. (6 p.m. ET), officials said.
"Yesterday's inmate-on-inmate altercation lasted less than two minutes with staff responding very quickly to quell the disturbance," the Oklahoma Department of Corrections said in a statement Sunday.
But it took prison staff another 38 minutes to secure the single housing area where the killings took place, officials said.
The facility, which is operated by the Corrections Corporation of America, houses 1,720 medium- and maximum-security male inmates.
The prison was on lock down Sunday while officials investigated, a release said, and three inmates remained in local hospitals in stable condition.
Officials have not released the names of the inmates involved.