At least 21 people were hurt, two of them seriously today when a Los Angeles commuter train struck a car that was crossing the tracks and derailed into a street near the University of Southern California campus.

A silver Hyundai Sonata was left crumpled and unrecognizable following the collision, according to a Reuters witness. The lead train car jumped the tracks, crashing through a metal fence and across a grass-covered median before coming to rest in the middle of Exposition Boulevard.

One person on the Metrolink train suffered serious injuries, the Los Angeles Fire Department said, and a person extricated from the car was in critical condition.

Nineteen others suffered minor injuries, according to the fire department, and emergency responders set up a triage area on a lawn in front of the Natural History Museum of Los Angeles, where patients were being treated.

Exposition Boulevard, a main thoroughfare through downtown Los Angeles, was shut down in both directions as crews surrounded the white, black and yellow train, which is painted with "Heads up, watch for trains," in large letters on the side.

The LAFD had said initially that two vehicles were involved. The cause of the wreck was not immediately known.

The crash was the latest among several train and road vehicle wrecks to occur in different parts of the United States over the past few months.

In February, about 50 people were hurt and an engineer fatally injured when a Los Angeles-bound Metrolink train struck a pick-up truck, flipping over three double-decker rail cars and tearing apart the truck.

Three weeks earlier in a suburb of New York City, six people were killed when a Metro-North commuter train struck a car at a crossing and derailed.