US sprinters fire relay warning

China's anti-doping agency on Thursday called for an independent probe into its US counterpart, after a media investigation found that American authorities allowed athletes who failed drug tests to continue to compete.

The report by the Reuters news agency on Wednesday said the global and US anti-doping authorities were in disagreement over the American side's tactic of allowing athletes who tested positive for banned substances to avoid prosecution in return for giving undercover information on other drug cheats.

The World Anti-Doping Agency (WADA) said the strategy by the US authority (USADA) was "in direct contravention of the World Anti-Doping Code" and "threatened the integrity of sporting competition".

The China Anti-Doping Agency (CHINADA) said Thursday that it "strongly calls for an independent investigation into USADA's cover-up of serious violations" of the code designed to prevent athletes from taking illicit substances that improve performance.

"USADA's practice... seriously damaged fair competition in sports and the rights and interests of clean athletes, and showed that its anti-doping work lacked transparency," CHINADA said. AFP