SAN DIEGO — Authorities now say at least six inmates have been injured, two seriously, in a riot at a state prison in San Diego.

Cal Fire San Diego Capt. Thomas Shoots says the riot erupted shortly after 8 p.m. in a yard at Richard J. Donovan Correction Facility.

Shoots tells the San Diego Union-Tribune that roughly 100 prisoners were in the yard at the time. He says two inmates were seriously injured enough that they were taken to hospitals by air ambulances.

Fights and riots have injured several inmates this year.

Three were seriously injured when seven other prisoners attacked them in April. And 10 were hurt, one seriously, in a February riot.

Last December, two inmates were stabbed in a yard fight.