A truck loaded with yellow phosphorus exploded in the early hours of Friday morning on an expressway in central China's Hubei Province, with the number of casualties unknown.

The firefighting division of Wuhan, Hubei provincial capital, received reports of the explosion at around 2:46 a.m., saying the accident occurred a kilometer away from a service zone along the Shanghai-Chongqing Expressway.

The truck was loaded with 40 barrels of yellow phosphorus, a volatile, toxic chemical that is highly flammable and self-igniting upon contact with air.

Firefighters have rushed to the scene and rescue work is under way.