WASHINGTON, July 14 (Xinhua) -- American sprinter Tyson Gay was tested positive in doping control on May 16, and the 30-year-old athlete decided to quit the Moscow world championships next month.

Gay failed an out-of-competition doping test by the U.S. Anti-Doping Agency on May 16. He didn't release information about what the substance was. He would have his "B" sample tested for a further step.

"I don't have a sabotage story. I don't have any lies. I don't have anything to say to make this seem like it was a mistake or it was on USADA's hands, someone playing games," said Gay.

"The B sample will be processed shortly, and as in all cases all athletes are innocent unless or until proven otherwise through the established legal process, and any attempt to sensationalize or speculate is a disservice to due process, fair play, and to those who love clean sport," announced USADA in a statement.

Gay, who won three gold medals at 2007 world championships, had signatured himself as a man of "clean competition". Gay was one part of USADA "My Victory" program, which encouraged clean competition.

"My career and my name have always been better than medals or records or anything like that. I've always wanted a clean name with anything. Unfortunately, I have to break this news, that I have a positive 'A' sample," said Gay.

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