The incident was reported at about 10:15 a.m. in the intersection of Arcadia and Main streets in Los Angeles.
A van reportedly ran a red light, struck a sheriff's vehicle, and overturned. Emergency officials said seven people were transported to area hospitals. Four were reported in serious condition, and three were reported in fair condition.
Sheriff's officials say a male deputy was driving the LASD Community Services cruiser with the lights and sirens off at the time of the incident. The deputy was checked out for injuries, which were described as "not serious."
Details surrounding the circumstances of the collision were not immediately released.