Los Angeles (US): A 11-hour riot, at the Reception Center West at the California Institution for Men in Chino, about 40 miles east of Los Angeles, on Saturday night and Sunday morning, has left 250 prisoners injured and 55 being admitted to hospital.
Black prison gangs fought Latino gangs in hand-to-hand combat; the New York Times quoted the prison authorities, as saying.
No prison employees were injured and no deaths were reported.
The riot has, however, led to 10 of the state's 33 prisons being placed in lockdown mode to prevent the unrest from spreading.
Damage to the 1,300-inmate medium-security prison was "significant and extensive," said a spokesman, Lt. Mark Hargrove.
One housing unit was virtually destroyed by fire, Hargrove said, adding that prisoners had smashed windows, torn down gates and used whatever they could to battle one another in the riot.
With more than 150,000 inmates, the California prison system is one of the most crowded in the nation, with many of its facilities holding more than double the number of inmates they were designed for.
The Chino prison is trying to put into effect a 2005 Supreme Court decision that prohibits automatic and systematic racial segregation of prison inmates after more than three decades of racial separation in the corrections system.
Prison officials said they were still questioning inmates to understand what set off the uprising. They said no demands or complaints had been directed at the guards. (ANI)