LOS ANGELES, Feb 04, 2013 (AFP) - At least eight people were killed and more than 30 were injured in a multiple vehicle accident in southern California that involved a passenger bus from Mexico, officials said.

The accident occurred at about 6:30 pm local time (0230 GMT Monday) in a rural area north of of the town of Yucaipa.

The bus, operated by InterBus Tours, a Tijuana, Mexico-based company, apparently hit two other vehicles and rolled over, local fire department chief Ronald Walls told reporters.

In all, 43 people were involved in the crash, 38 passengers and the driver on the bus and two people in each of the other vehicles, according to Walls.

It took firefighters more than two hours to extricate all the injured from the wreckage. In all, 27 were taken to area hospitals, at least six of them in critical condition. Some of the injured were children.

A representative of the Mexican consulate was at the scene.

Bus going to ski resort

According to media reports, the bus was headed back to Tijuana after visiting Big Bear Lake, a popular mountain ski resort northeast of San Bernardino.

Witness Betty Harvey, a local resident, was driving behind the bus and thus was one of the first to arrive at the scene.

"People were waving and screaming," she said. "It was quite horrific."

Details of the tragedy remain sketchy.

"It happened so fast, I don't know how it all happened," one unnamed passenger told The San Bernardino Sun newspaper. "This was supposed to be a good day out with my companions and then this happened."

InterBus official Jodi Garcia said initial examinations point to brake failure as the cause of the crash.

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

San Bernardino County Fire Department spokesman Eric Sherwin said some people were trapped inside the overturned bus and had to be removed by emergency personnel.

"Those injured range from minor to life-threatening," Sherwin explained.

A spokesman for Loma Linda University Medical Center told The Los Angeles Times that the hospital had received four victims from the crash -- two adults and two children. One adult and one child were in critical condition.

"We're expecting more people from the crash," the spokesman, Herbert Atienza, is quoted as saying.

Highway 38, where the accident occurred, was closed for traffic in both directions.