Two of the injured were in critical condition, one was in the train and the other inside the vehicle
Shan Lenske, Fire Department spokesman, said the accident happened shortly before 11 in the morning local, near the campus of the University of Southern California (USC).
So far the causes of the accident are unknown.
Reuters reports that of the 21 injured, two are serious. The accident occurred when a passenger train from Los Angeles collided with a vehicle that crossed the railway. A witness reported that the vehicle was a Hyundai Sonata that was unrecognizable from the impact.
The two serious people are a Metro link passenger train and a passenger was removed from the vehicle.