PRISON RIOT'S TRAIL OF DEVASTATION

Blood-soaked mattresses, singed bedding and abandoned medical supplies littered the prison, after the riot which left 175 inmates injured, some critically.

Prison officials staged a tour of the devastation at the jail in Chino to reveal the extent of the racially motivated riot that broke out on Saturday evening and raged for four hours before guards could bring it under control.

Seven of the eight units in the prison's Reception Centre West, one of several housing areas, were left uninhabitable, and more than 1,100 inmates have been moved to other facilities. One of the dorms was completely gutted by flames.

Eleven inmates remain in hospital, state prisons spokesman Terry Thornton said.

Officers have scanned the exercise yard with metal detectors, searching for home-made weapons that inmates might have buried.

The riot began in a dorm during dinner hour and quickly spread, temporarily overwhelming staff, said Lieutenant Mark Hargrove, a prison spokesman.

Prisoners pulled heavy metal grates from windows to escape and scrambled up and over the dorm roofs to get around 10ft-tall hurricane fencing intended to keep them from the main exercise yard. The fence was installed after a previous riot in 2006.

The prison was built in 1941 to house 3,000 inmates but held 5,900 men at the time of the riot.

Each dorm holds 198 inmates and is assigned two guards, with a third guard who roams between every two dorms.