Fourteen people have been killed and 31 injured when a fire erupted on a public bus in northern China.

The vehicle “suddenly caught fire” on Tuesday morning near a public square in Yinchuan, officials in the capital of the remote Ningxia region said on a verified social media account.

The cause of the blaze was still being investigated, the post said, adding that 31 people were being treated in hospital.

Meanwhile, China's state-run Xinhua said that arson was being suspected as the cause.

The incident happened at about 7am.

A press officer at the Ningxia fire department said firefighters put out the fire in 10 minutes.

(With inputs from AFP, AP and Xinhua)