Gatlin fails drugs test

"I have been informed by the United States Anti-doping Agency that after a relay race I ran in Kansas City on April 22, I tested positive for "testosterone or its precursors," Gatlin said in a statement.

"I cannot account for these results, because I have never knowingly used any banned substance or authorised anyone else to administer such a substance to me."

"Since learning of the positive test, I have been doing everything in my power to find out what caused this to happen.

"I have been and will continue to cooperate fully with USADA as it moves forward with the process it has initiated and hope that when all the facts are revealed it will be determined that I have done nothing wrong."

Gatlin's B sample test in July also produced an unusually high level of testosterone.

Gatlin is the joint World Record holder over 100m with Asafa Powell of Jamaica (9.77s) although has been absent for many of the big meetings this season through injury.

The 24-year-old American also won the 200m at the World Championships in Helsinki and faces a life ban if found guilty after failing a drugs test as a youth on account of medication for an attention deficit disorder containing an amphetamine.

"That experience made me even more vigilant to make certain that I (do) not come into contact with any banned substance for any reason whatsoever, because any additional anti-doping rule offence could mean a lifetime ban from the sport that I love," Gatlin added in his statement on Saturday.

"Since the positive test at the University of Tennessee, I have been involved with efforts to educate people about the dangers of using drugs and would never do anything to disappoint my fans and supporters," said Gatlin.

"It is simply not consistent with either my character or my confidence in my God-given athletic ability to cheat in any way."