A bus caught fire in northern China on Tuesday, killing 14 people and injuring more than 30, a fire spokeswoman said.

The incident happened in Yinchuan, the capital of Ningxia region, at around 7 a.m., and the cause of the fire is still being investigated, said a press officer at the Ningxia fire department, who only gave her surname, Wang.

She said firefighters put out the fire in 10 minutes, and that 14 people died and 32 were injured.

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