Eight people were killed and a further 38 were injured when a tour bus smashed into a truck and a second vehicle on a rural mountain highway near Yucaipa, California.

Eight people were killed and a further 38 were injured when a tour bus smashed into a truck and a second vehicle on a rural mountain highway near Yucaipa, California, east of Los Angeles.

Witnesses reported that the bus hit a truck around 6:30pm on Sunday, and then rolled down an embankment. It was initially reported that up to 10 people had been killed, but that figure was later reduced.

The accident involved three vehicles: The tour bus, a sedan and a pickup truck pulling a trailer.

The bus driver reportedly had brake problems while descending the mountain road, rear-ending a sedan, flipping the bus over and then hitting a truck, officials said.

At least seven ambulances arrived at the scene, and the injured were taken to several nearby hospitals. In total, 39 people were aboard the bus and four other people were in the other two vehicles.

The California crash came less than a day after at least 35 people were injured when a charter bus carrying 42 passengers struck a low bridge in Boston.