At least 42 people have died and 33 others were injured in a rush hour bus fire in southeast China.

An express bus burst into flames while on an elevated roadway in the prosperous port city of Xiamen, state media reported.

A local fire official who only gave his surname, Sun, said bodies were piled up inside the bus. He said the cause of the fire was being investigated.

Xinhua News Agency quoted a survivor as saying she smelt petrol and then saw a fire spreading rapidly.

An official news site, Xiamen Net, said witnesses heard sounds of explosions after the fire had been burning for about 10 minutes.

China’s public transit has been expanding rapidly over the past decade, but there are worries that the country is sacrificing safety in its rush to roll out modern services.