At least five people were killed and 20 others injured when a truck, suspected to be carrying flammable materials, exploded on a highway in central China’s Hunan Province, authorities said today.

The truck suspected to be loaded with flammable and combustible materials had exploded last night on a section of the highway linking Beijing to Hong Kong and Macao in Yueyang City.

Two cars and two trucks caught fire and another seven vehicles were damaged by the explosion, provincial traffic authorities said.

Among the injured, four are still in critical condition, state-run Xinhua news agency reported today.

Further investigation is under way.