LA PAZ, April 22 (Xinhua) -- At least 11 people were killed and several others were injured when a bus fell into a ravine about 100 meters deep on a highway in western Bolivia Sunday night, authorities reported on Monday.

The accident occurred in the town of Yolosita when a bus, carrying 45 people from La Paz to Rurrenabaque in the northern department of Beni, apparently collided with another vehicle and ran off the highway, according to preliminary reports.

Speeding might have been one of the factors that led to the accident, in addition to the danger of the road, said Angel Rojas, commander of the highway patrol, who added that it was "preliminary information that investigations will determine later."

The injured people were taken to the Arco Iris Hospital in La Paz, where they were treated in the emergency department, Rojas said, adding that several of them are in serious condition.