CHANGSHA - A bus loaded with 48 people fell off a cliff in the city of Yongzhou in central China's Hunan province Thursday afternoon, leaving at least four people dead, local authorities said.

The accident happened at 5:50 pm. The bus, which has a capacity of 49, was on its way from Daoxian County to Yongzhou.

Most of the passengers were students from Daoxian bound for a school in Yongzhou, where they were scheduled to sit an exam.

"Many" passengers were injured, eight of them seriously, said the municipal government. All the injured have been sent to a local hospital, but the number of casualties is not yet known.

Search and rescue work is ongoing at the scene, and the director of the municipal work safety administration is en route to the crash site.