Chinese swimmer Chen Xinyi has failed a doping test at the Rio Olympics, the official Xinhua news agency reported Friday, citing the Chinese Swimming Association (CSA). Meanwhile, Bulgarian athlete Silvia Danekova confirmed that she had failed a doping test at the Olympics in Rio, with Bulgarian television saying she tested positive for blood booster EPO.

Chen tested positive for hydrochlorothiazide, a diuretic, on Sunday, it said. On that day the 18-year-old came fourth in the women's 100m butterfly final -- just 0.09 seconds away from a place on the podium.

Chen has applied to the International Olympic Committee for her B sample to be tested and for a hearing, it added.

The 33-year-old Silvia also insisted on her innocence: "I am not guilty, I have done nothing wrong. Four tests were done, three of them were negative. We found out that my fourth test was positive."