GUANGZHOU - A blast triggered by oil leaked from a tank truck killed 20 people and injured 14 others early Friday in South China's Guangdong province, local authorities said.

The tank truck carrying 40 tons of gasoline collided with another truck at 4:34 am on the Yanjiang Expressway in the provincial capital Guangzhou. After the crash, oil leaked from the tank and triggered an explosion, said the city's Internet information office on its official microblogging site.

As of 10 am, 20 people were confirmed dead and another 14 people were wounded, one among whom suffered severe injuries, said the posting.

The blast set ablaze a timber mill and some work sheds under the expressway bridge.

Firefighters have evacuated the factory and work sheds and the fire has been brought under control.

Sources said that most of the casualties were workers of the factory.