CHINO, Calif. (AP) - A state prison remained locked down Monday and more than 1,000 prisoners were being moved after a weekend riot that burned a wooden dormitory and left 175 inmates injured.
Saturday's fight at the California Institution for Men in Chino left 55 prisoners seriously injured but only 30 remained hospitalized Monday with non-life threatening injuries, said state prisons spokeswoman Terry Thornton.
Thornton said more than 1,000 inmates are being temporarily moved to other facilities because of damage to some dormitories, most of them to a vacant youth detention center.
The Chino prison holds 5,900 men but was designed for 3,000. Thornton said it's unclear what role overcrowding played in the riot.
"Overcrowding is a problem but to make the assumption that it caused this incident, I don't think you can make that assumption," Thornton told The Associated Press.
A prison spokesman said earlier that tension between black and Hispanic prisoners may have sparked the fight.
There were 120 prisoners treated for injuries at the scene and another 55 were taken to a hospital for treatment of serious injuries, such as stab and head wounds.
Chino and nine other Southern California prisons were closed to visitors - nearly a third of the 33 state prisons - because staff from those prisons were temporarily shifted to Chino to help clean up the riot's aftermath.
Thornton said the fighting began at 8:30 p.m. Saturday and went until about midnight. However, staff needed until 7 a.m. Sunday to clear the last building, she said.
The outbreak occurred at a reception center that accepts new inmates and parole offenders being processed to be housed at the prison and sent to other facilities in the state, officials said.
Prison staff became aware of a plan to carry out a riot Thursday night, prison spokesman Lt. Mark Hargrove told the Riverside Press-Enterprise. The prison was placed on a modified lockdown, which included feeding inmates in their cells and restricting movement around the property. That lockdown continued until Saturday when the riot began.
Still, the inmates inflicted serious damage to the facility and one another.
Hargrove did not immediately return calls from the AP on Monday.
Curt Hagman, a state assemblyman for the district that includes Chino, believes the riot was a "coordinated attack."
"They all knew what they were going to do in starting a big brawl," Hagman told the Press-Enterprise. He added that inmates used improvised weapons and broken glass to stab each other.
The disturbance was the prison's most violent since a December 2006 uprising in which 200 inmates rioted for 90 minutes. That racially charged incident was touched off by a fight between a Latino and a black inmate.