BEIJING - THE International Gymnastics Federation (FIG) told China on Saturday to provide more evidence to support its claims that five of its Olympic gymnasts are old enough to be competing.

Allegations have been rife that China broke the rules by fielding gymnasts who will not turn 16 this year as required under the sport's rules introduced in 1997 to protect the wellbeing of young athletes.

'The International Gymnastics Federation (FIG) is seeking to clarify the claims made in the media regarding the age of Chinese female gymnasts He Kexin, Jiang Yuyuan, Li Shanshan, Deng Linlin and Yang Yilin,' it said in a statement.

But more evidence focusing on the age of gold medal winner He Kexin has surfaced in recent days prompting the International Olympic Committee to demand the FIG check again.

The FIG said that 'in the interests of laying the matter to rest ... the FIG has now asked the Chinese Gymnastic Association to submit further documents testifying to the birthdates of the gymnasts'.

'On receipt of these documents, the FIG will forward its conclusions to the International Olympic Committee. It is in the interests of all concerned, not least the athletes themselves, to resolve this issue once and for all.'

BOCOG executive vice president Wang Wei insisted on Friday that the gymnasts would not have competed if they were under-age, while He told reporters during the competition that she was 16.

USA Gymnastics president Steve Penny on Friday said he had long believed the issue needed addressing by the FIG and IOC.

'An investigation would help bring closure to the issue and remove any cloud of speculation from this competition,' he said.