YUCAIPA, California (AP) -- At least eight people were killed and more than three dozen injured when a bus careened out of control while travelling down a Southern California mountain road, struck a car, flipped and plowed into a pickup, authorities said.

California Highway Patrol spokesman Mario Lopez said the eight confirmed deaths was expected to rise because the coroner was just starting to remove bodies from the mangled vehicle and also remove the bodies of those who were ejected, which were covered by yellow blankets.

"It appears speed was a factor in this collision," Lopez said. Investigators will determine if mechanical failure or driver error was to blame, he said. The driver survived.

Authorities had not yet obtained the passenger list from inside the bus, Lopez said.

The accident occurred around 6:30 pm Sunday about 80 miles east of Los Angeles and left State Route 38 littered with debris, the bus sideways across the two lanes and its front end crushed.

The bus was returning to Tijuana, Mexico, Lopez said. It rear-ended a Saturn sedan and hit a Ford pickup, he said. One person in the pickup was injured. The fate of the passengers in the car was not clear, but at least two people were in it, Lopez said.

California Department of Transportation spokeswoman Michelle Profant said the scene was shocking.

"It's really a mess up there with body parts," she said.

The bus driver told investigators the bus suffered brake problems as it headed down the mountain, Lopez said.

Lettering on the bus indicated that it was operated by Scapadas Magicas LLC, a company based in National City, California. Federal transportation records show that the company is licensed to carry passengers for interstate travel and that it had no crashes in the past two years.

A call to the company was not immediately returned.

Jordi Garcia, a manager for InterBus Tours, said his company ran Sunday's trip. He told U-T San Diego that 38 people departed Tijuana at 5:00 am for a day of skiing at Big Bear.

"The information that we have is that the bus' brakes failed and the accident occurred," he said.

Patients were taken to several area hospitals with injuries ranging from minor to life-threatening.