Nine people were killed and four were missing in eastern China on Wednesday after the collapse of a structure that housed workers building a railway line, state media reported.

Twenty-one other people were injured and taken to hospital following the accident in Jiangsu province along a rail link being built between the cities of Shanghai and Nanjing, Xinhua news agency said.

Xinhua had earlier reported the accident as along the Beijing-Shanghai high-speed rail line, which China hopes will be among the world's fastest when finished in 2012.

But the agency subsequently corrected the location, without explaining the mistake.

Xinhua gave no other details on the accident, which occurred in the city of Danyang. It said an investigation had been launched into the cause.

Earlier Xinhua reports quoted a rail official saying a gas tank explosion triggered the accident.

China has in recent years embarked on plans to expand its rail network, already the world's most extensive.

It recently approved a two-trillion-yuan ($290-billion) investment plan for its railway infrastructure over the next two years in a bid to spur growth in the face of the global economic crisis.

Deadly workplace accidents are common in China, where awareness and enforcement of basic safety practices is lax.

AFP