A fire department official says a fire on a bus in northern China has killed 14 people and injured more than 30.

The incident happened in Yinchuan, the capital of Ningxia region, on Tuesday morning.

A press officer at the Ningxia fire department says the cause is still being investigated.

She says 14 people died and 32 have been injured.

She gave only her surname, Wang.

There have been several serious bus fires in recent years in China, some blamed on people who are mentally unstable or who are seeking revenge against society.