BEIJING -- A work safety bureau in southwest China said a bus fell off a cliff in Sichuan province, killing 13 people and injuring nine.

The Sichuan provincial work safety bureau said Sunday that the bus fell 28 feet (8.5 meters) during the accident the previous afternoon. The cause of the accident was still under investigation.

Xinhua News Agency said the bus lost control and crashed into a guardrail before falling off the cliff.

Road accidents are common in China because of overloaded and unsafe vehicles, poor road conditions and bad driving habits. (AP)