The indoor stadium being built for next year`s 11th China National Games in Jinan was damaged by a fire that broke out on Sunday evening, state media reported.

The lotus-shaped indoor stadium of Jinan Olympic Sports Center in Shandong province, under construction to stage the ball games next October, burned for nearly five hours until 300 firefighters put it out with the help of rainfall.

There were no casualties but a quarter of the roof was destroyed, said Xinhua.

"The operation of electric welding ignited inflammable thermal insulation material," Xinhua quoted the local authorities as saying.

China`s National Games, held every four years, is one of the world`s biggest sporting events with nearly 10,000 athletes taking part.