LOS ANGELES (Reuters) - Corrections officers firing pepper spray and plastic rounds quelled a "large-scale riot" by about 150 inmates on Friday at the maximum-security California State Prison-Sacramento, prison officials said.
Two inmates suffered multiple stab wounds in the melee, which erupted just after 10 a.m. local time in an outdoor exercise yard, according to a statement issued by the state Corrections and Rehabilitation Department.
Both of those prisoners were admitted to an outside hospital, and at least one underwent surgery there, prison spokesman Tony Quinn told Reuters.
Two other inmates also were treated at hospitals, then released back to the prison, while others with relatively minor injuries were being examined at the prison, Quinn said. No prison staff were injured in the riot, he added.
Quinn said investigators were reviewing surveillance footage to determine what sparked the riot, which he said lasted about five minutes, and whether all 150 prisoners in the yard at the time were actually involved.
For now, the disturbance appears to rank as one of the larger riots at the prison in the last 15 years. But some of the inmates in the yard "might have been trying to get out of the way" when trouble started, he said.
"Staff utilized less-lethal rounds, pepper spray and one lethal round (warning shot) to quell the incident," the corrections statement said. Quinn said less-lethal rounds consist of hard-plastic foam.
Quinn said the entire prison was locked down, with inmates confined to their cells, for at least six hours following the outbreak of violence.
He said a lockdown would likely remain in place through the weekend for the B-Facility where the trouble occurred, while restrictions were gradually lifted elsewhere in the prison.
The sprawling facility near Folsom State Prison, north of Sacramento, houses roughly 3,000 inmates, and employs some 1,700 staff.
Opened in 1986, the facility houses primarily prisoners serving long sentences and those that have proved to be management problems at other institutions, "so we have some of the bad boys here," Quinn said.
(Reporting and writing by Steve Gorman; Editing by Greg McCune)