Chinese swimmer Chen Xinyi tests positive at Rio 2016

Rio de Janeiro - A female Chinese swimmer has tested positive for a banned substance at the Rio Olympics, China's swimming association said Friday - the first competitor in the sport to fail a test at the games.

The Chinese Swimming Association said Chen Xinyi tested positive for the diuretic hydrochlorothiazide after she finished fourth in the women's 100-meter butterfly Sunday, missing a bronze medal by nine-hundredths of a second. Xinhua, China's official state news agency, reported the story Friday.

The 18-year-old was also scheduled to compete in the 50 meter freestyle beginning Friday.

Chen has applied to the International Olympic Committee to have her B sample tested and to get a hearing on the matter, Xinhua said, citing the swimming association.

''The CSA has taken this matter seriously and demanded full cooperation from Chen in the investigation,'' the association said in the statement quoted by Xinhua.

Chen's result comes as doping has been a major concern in the Rio Games.

Seven Russian swimmers have been allowed to compete in Rio after initially being banned following allegations of a huge, state-sponsored doping operation in their homeland. That decision has sparked vocal complaints from several swimmers, most notably American Lilly King.

No statement about Chen's reported test was posted to the website of the Chinese Swimming Association, and calls to its offices rang unanswered on Friday. FINA, the international governing body of swimming, did not immediately respond to a request for comment.

Chen's teammate Wang Shun declined to comment after he won bronze in Thursday's 200-meter individual medley.

''This situation, I don't know the details,'' Wang said.

Li Keke, a spokeswoman for China's national anti-doping agency, said she had no additional information on the Chen case.

''We have noticed media reports about the case. So far the anti-doping agency has yet to receive any official confirmation,'' Li told The Associated Press.

''This reported test should be generated by the organizer. The Olympic committee and FINA should know about it. At present, we will continue to monitor,'' Li said.