Story highlights Chen Xinyi tested positive for a drug used as a diuretic

China's sensitive to drug claims after spat between swimmers Mack Horton and Sun Yang

(CNN) A Chinese swimmer has failed a drugs test at the Rio Olympics, according to China's state-run news agency Xinhua, citing the China Swimming Association (CSA).

Chen Xinyi tested positive on August 7 for hydrochlorothiazide, a banned substance which acts as a diuretic.

Chen's case is being considered by the Court of Arbitration for Sport (CAS) and the China Swimming Associated said it would respect its final decision, Xinhua said.

Chen Xinyi, 18, has already competed in the 100-meter butterfly event, placing fourth in the final held on Monday, according to the Rio Olympics official web site.

She is next scheduled compete in the 50-meter freestyle on Friday. .