BEIJING — X-ray bone analysis of 15,000 young Chinese athletes shows about 20 percent have lied about their ages, provincial sports authorities say.

The analysis was conducted by sports officials in southern Guangdong province and reported on the Web site of the Southern Metropolis Daily.

The confirmation of age-faking again puts pressure on Chinese sports officials. Several of China's gold-medal winning female gymnasts at last year's Olympics were widely suspected of being underage, although they were later cleared by officials of the sport's world governing body.

NBA player Yi Jianlian is also widely reported to have falsified his age on Chinese documents. Late last year China's Sports Ministry reported that it found 36 players in China's professional basketball league whose dates of birth may have been changed.

The newspaper reported that Guangdong authorities found that 2,000 athletes were no longer eligible to compete in youth events. It said another 1,000 need to compete in different age categories.

The southern city of Guangzhou will host next year's Asian Games, and provincial officials appear to be cracking down beforehand.

"We won't allow those who faked their age to get any benefit at all," said Ye Xiquan, deputy director of the provincial sports bureau.