LONDON -- British sprinter Dwain Chambers became the first athlete to admit testing positive for a previously undetectable designer steroid at the center of a potential drug scandal involving U.S. athletes.

But Chambers' attorney, Graham Shear, said his client wasn't trying to cheat and believed the supplements he was given were within international rules.

"My client wants to clarify that he will not accept nor tolerate any accusation or implications that this was a willful or calculated attempt on his behalf to deceive the authorities," Shear said in a statement.

Chambers trained in the United States with Remi Korchemny and worked with Victor Conte, founder of the Bay Area Laboratory Co-Operative, or BALCO, which is being investigated by a federal grand jury. The scope of the grand jury probe is unclear.

Chambers said he was assured by Conte that all the supplements he was given were within international rules, Shear said.

Conte has been accused by the U.S. Anti-Doping Agency of supplying athletes with the steroid tetrahydrogestrinone, or THG. He has denied that.

Shear said Chambers underwent an out-of-competition test in Germany in August and was notified early this month that his A sample was positive for THG. He said Chambers' B sample had yet to be tested and the sprinter will "cooperate fully" with the investigation.

The USADA said last week it retested hundreds of samples from track and field athletes after identifying THG, and that several tested positive during the U.S. track championships in June.

If found guilty of a doping offense, Chambers would face a ban of two years and miss next year's Olympics in Athens.

Britain could also lose the 400-meter relay silver medal it won at the World Championships in France in August. Chambers ran the final leg in the race.