At least six people were killed and hundreds injured in a blast and ensuing fire on Wednesday morning at a plastics and chemical factory in eastern China, Xinhua news agency reported.

A powerful explosion in the city of Nanjing, the capital of eastern China's Jiangsu Province, ripped through the abandoned factory at about 10:10 a.m. local time damaging nearby buildings and cars within the range of 100 meters (some 330 feet).

Xinhua reported that the blast also hit a passenger bus injuring many people inside the vehicle.

Other Chinese media sources estimate the number of injured people at some 300 with many of them in critical condition in hospitals.

Firefighters are still combating the fire at the plant and the final number of casualties will be established later.

A preliminary investigation established that the blast was caused by a gas leak from a pipeline running through the plant, Xinhua said.

BEIJING, July 28 (RIA Novosti)