Former world 100 metres record holder Tim Montgomery has announced his retirement from athletics, one day after receiving a two-year doping ban from the Court of Arbitration for Sport (CAS).

"I'm done. I have retired," Montgomery told Reuters in a telephone call from his residence in Hampton, Virginia on Wednesday.

Montgomery and fellow American sprinter Chryste Gaines were each banned for two years after CAS accepted evidence the pair had taken the designer steroid THG (tetrahydrogestrinone), the product at centre of the BALCO laboratory doping scandal.

The 30-year-old Montgomery, however, vehemently denies ever knowingly taking a banned substance.

The Lausanne-based CAS said it had accepted evidence that both athletes told double world sprint champion Kelli White they had been taking THG.

Montgomery denied telling White in a conversation in 2001 that he had used the steroid.

"She said she told me, 'It (THG) made me tight'," Montgomery told Reuters.

"I had just ran 6.46 seconds (for 60 metres), the best time I had ever run. So I was complaining... she was the one who had cramped up.

"If they (CAS) went by the evidence, they would have never have had a case.

"I feel like the process was totally not fair. From where I come from, you need a positive test."

But CAS affirmed the U.S. Anti-Doping Agency (USADA) had the authority to bring cases against athletes based on evidence of doping rather than a positive test.

USADA said it also presented detailed evidence of blood and urine tests of each athlete over a period of years, along with corresponding expert testimony confirming that the pattern of testing results was consistent with doping.

'THE CLEAR'

Montgomery also countered a newspaper report indicating he admitted to a federal grand jury investigating BALCO that he had used banned substances.

The San Francisco Chronicle reported last year that Montgomery told the grand jury that BALCO founder Victor Conte gave him weekly doses of growth hormone and a steroid-like drug known as "the clear" over an eight-month span in 2001.

"They (the grand jury) asked me if I had taken anything under my tongue. I said 'no'," Montgomery said.

"They asked me did I take any liquid. I said 'yes'. They asked me was the liquid THG. I said 'no'. I never heard of THG before."

However, Montgomery said he did tell the panel he had taken flaxseed oil, which looked similar to a tube of THG he was shown in front of the grand jury.

"They asked me if I had taken steroids and I said 'no'," he added.

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Montgomery said he began his working with Conte in January 2001 after meeting with him the previous November.

He confirmed there had been a 'Project World Record' involving Conte and former Canadian coach Charlie Francis.

"But it was for everybody in (Conte's) ZMA club," Montgomery said. "I was the one who broke the world record."

Montgomery set the world record of 9.79 seconds in September 2002. Jamaican Asafa Powell [Images] has since set a faster mark of 9.77 in June this year.

As part of his ban, Montgomery's time was removed from the record books.

JONES SPLIT

The sprinter also confirmed he had split up with his partner Marion Jones [Images], the triple Olympic champion from the 2000 Sydney Games, who Montgomery believes is also under investigation.

"It's kind of hard to be in the same household when you are going through some of the same things," he said.

"We decided to remain friends so we can concentrate on making a future for our (two-year-old) son. We decided to make a decision to better ourselves for our kid."

He added: "Before I take my son's mother down, I will go down myself."

Jones has never been charged with a doping violation by USADA and has never failed a doping test.