Gatlin tests positive for prohibited substances

Another American champion was hit with a shocking positive drug test Saturday -- Olympic and world 100-meter champion Justin Gatlin.

Gatlin said he has been informed that he tested positive for testosterone or other prohibited steroids -- the same violation that, only two days ago, threw Floyd Landis' victory in the Tour de France into question.

Gatlin said in a statement released through his publicist that the U.S. Anti-Doping Agency informed him of the test taken after a relay race in Kansas in April.

He said he will cooperate with USADA "and hope that when all the facts are revealed it will be determined that I have done nothing wrong."

"I cannot account for these results, because I have never knowingly used any banned substance or authorized anyone else to administer such a substance to me," Gatlin said. "In the course of my entire professional career, I have been tested more than 100 times. ... All of the tests this season, including the out-of-competition and in-competition tests conducted just before and after the race in Kansas, were negative."

Gatlin is the co-world record holder in the 100 meters.