"It is time to allow me to put this issue behind me once and for all and focus all of my energy on where it should be focused -- bringing home some gold medals for the USA in Athens," Jones said in a statement. "There is nothing more I can do."

Jones made the request after meeting with the USADA in an effort to defuse rumours swirling around the American sprinter amid growing concerns about steroid use among top track and field athletes in the wake of indictments against the San Francisco area BALCO lab earlier this year.

In recent weeks Jones has found herself increasingly at the centre of the doping storm, under intense pressure to explain her relationship with the Bay Area Laboratory Co-Operative (BALCO) believed to be at the heart of the steroid scandal.

Last week, Jones challenged USADA to retest her samples to show that she was drug free and appeared shocked after the anti-doping agency informed her they had no samples to retest.

"I can now report that we have learned from USADA that it has no knowledge of any past samples from which to re-test," Jones said.

"In short, USADA has no information regarding the more than 160 drug tests I have taken other than that each and every time I was tested the results were the same -- I was drug free.

"Drug free before the Olympics, drug free during the Olympics and drug free after the Olympics."

Jones has denied that the speculation upset her focus but with the Olympics less than 90 days away there have been indications the 27 year-old sprinter has become distracted by the investigation and growing weary of the constant questioning.

"WITCH HUNT"

At a meet in Carson, California on Saturday, Jones captured the 100 metres in a wind-aided time of 10.99 seconds and claimed the long jump with a wind-aided leap of 23 feet, 43/4 inches but later complained about the USADA's tactics, which her lawyer Joseph Burton had earlier described as a "witch hunt".

Burton added his voice to Jones', saying that in the absence of any evidence the USADA should back off and allow the sprinter to do what she does best.

"It is time for USADA to allow Marion to put this issue behind her once and for all and allow her to do what she does best: train, sprint and jump for gold medals on behalf of Team USA in Athens," Burton said in a statement.

"What she has accomplished is the result of her hard work and the natural talents she has been blessed with. And USADA's conduct absent any tests is unconscionable because it represents an effort to take away from her what she has rightfully earned. It is not fair. It is not right. It is not American.

"And it should come to an end now."