Questions persist over Armstrong
Lance Armstrong's insistence that he had stopped doping when he made his Tour de France comeback in 2009 has been challenged.
The 41-year-old Texan confessed to doping during all seven Tour de France title victories on the Oprah Winfrey show but was adamant he did not do so during his comeback.
The US Anti-Doping Agency has, however, produced evidence that he did, according to WADA president John Fahey.
Fahey told the Daily Telegraph: "The evidence from USADA is that Armstrong's blood tests show variations in his blood that show with absolute certainty he was doping after 2005. Believe USADA or believe Armstrong? I know who to believe.
"It struck me that the statute of limitations under US law might be relevant and Armstrong would not want to admit to anything in regards to his comeback (in 2009) that might be picked up under the US criminal code."
USADA meanwhile called on Armstrong to admit to the full extent of his drug use under oath.
USADA chief executive Travis Tygart said in a statement: "Lance Armstrong has finally acknowledged that his cycling career was built on a powerful combination of doping and deceit.
"His admission that he doped throughout his career is a small step in the right direction. But if he is sincere in his desire to correct his past mistakes, he will testify under oath about the full extent of his doping activities."
Britain's former Olympic road race champion Nicole Cooke branded Armstrong as "a disgusting human being" and his confessional interview with Winfrey as "a pantomime".
She told BBC Radio Five Live: "The sad thing is that there were clean riders who had livelihoods, whole careers stolen from them by that. We're probably not going to see those people vindicated in any way through this.
"He's got no morals - he is a disgusting human being.
"It is a pantomime to me. Lance Armstrong should have been taken to a court, not to an Oprah Winfrey sofa."
Betsy Andreu, the wife of Armstrong's former team-mate Frankie Andreu, who claimed she heard the 41-year-old telling doctors at Indiana University Hospital that he had used performance-enhancing drugs, was far from satisfied with Armstrong's confession.
"I'm really disappointed," she told CNN. "He owed it to me; you owed it to me Lance, and you dropped the ball. After what you've done to me, what you've done to my family, and you couldn't own up to it."
Emma O'Reilly, a former masseuse with US Postal who was branded "a whore" by Armstrong when she spoke out about his misdemeanours, said: "Not all the riders were comfortable with cheating as Lance was. You could see when they went over to the dark side their personalities change."
The International Olympic Committee, who yesterday stripped Armstrong of his bronze medal from the Sydney Games, issued a statement condemning his drug-taking.
The IOC said: "There can be no place for doping in sport and the IOC unreservedly condemns the actions of Lance Armstrong and all those who seek an unfair advantage against their fellow competitors by taking drugs.
"This is indeed a very sad day for sport but there is a positive side if these revelations can begin to draw a line under previous practices.
"We now urge Armstrong to present all the evidence he has to the appropriate anti-doping authorities so that we can bring an end to this dark episode and move forward, stronger and cleaner."