A freeway accident involving a big-rig truck killed at least seven people and shut down eastbound lanes of Interstate 5 (search), a main route between Northern and Southern California, authorities said early Saturday.

The big-rig and a sports utility vehicle apparently collided shortly after 10:30 p.m. Friday and at least four other cars may have been involved, a California Highway Patrol dispatcher said.

The identities of the victims and the cause of the crash were not immediately available, he said.

Television station KXTV in Sacramento (search) said video taken at the scene in Yolo County showed the sport utility vehicle crumpled under the front of the big-rig.

CHP Lt. Deb Schroeder in Sacramento told the station that it appeared traffic had slowed, perhaps because of road construction, when the rig apparently plowed into the back of the SUV and perhaps several other cars.

Woodland is about 18 miles northwest of Sacramento.