Lance Armstrong's lawyer has labeled the probe against the seven-times Tour de France winner "un-American" and a waste of money following fresh claims against the cyclist in the US media.
The New York Times published claims on Thursday from an un-named former team mate of Armstrong's on United States Postal Service saying that doping on the team was widespread and carried out with Armstrong's "knowledge and encouragement."
"This is a story full of anonymous sources and more inappropriate leaks of grand jury testimony designed to create a circus-like atmosphere," Armstrong's attorney Brian Daly said in a statement.
"The power of the federal government is being abused to pursue dated and discredited allegations, and that's flat-out wrong, unethical, un-American, and a waste of taxpayer dollars.
"To the extent that any riders are suggesting that Lance Armstrong violated cycling rules or doped, they are either mistaken or not telling the truth.
"Lance has ridden with hundreds of riders over the years who will support his position, and over all that time he has never failed even a single test," added Daly.
A grand jury has been convened in Los Angeles following allegations made by former Postal Service rider Floyd Landis.
Landis, who was stripped of his 2006 Tour title following a positive dope test, accused Armstrong and several other American riders of using performance-enhancing drugs.
Armstrong, who has faced doping allegations throughout his career but never tested positive, has repeatedly denied any wrongdoing.
The American was diagnosed with testicular cancer before going on to win seven successive Tours from 1999-2005.
