​​​​​​​ANKARA

The World Anti-Doping Agency (WADA) urged "root and branch reforms" in a statement Tuesday for the system in the US.

WADA highlighted that 90% of American athletes remain outside the jurisdiction of the agency's code, in a letter to Tobie Smith, chair of the US Anti-Doping Agency (USADA) board of directors.

"Of primary concern is the matter of college sports, which account for so many athletes who go on to compete at the very highest levels, including the Olympic Games," said WADA. Seventy-five percent “of U.S. athletes competing in Paris came through the collegiate system. That is three-quarters of American Olympians who were at one time part of an elite system that operates far below the globally recognized clean sport standard."

WADA indicated that it has concerns for the welfare, performance and health of the US athletes, "We are sure it horrifies you to know that top overseas athletes may be taking 'doping vacations' on U.S. soil."

WADA also criticized USADA's testing performance as inadequate because it collected 7,773 samples from 3,011 athletes, which is a small number given the country's population and large pool of athletes, according to the statement.

The agency noted that it has a mandate to ensure the rules are upheld consistently, regardless of which country or sport is involved.

China's Anti-Doping Agency (CHINADA) urged athletics' doping watchdog last Thursday to increase testing of American track and field athletes after sprinter Erriyon Knighton tested positive for the prohibited substance trenbolone.