PARIS (AP) -- The head of the U.S. Anti-Doping Agency wants Lance Armstrong to come forward with information detailing the alleged complicity of cycling's governing body in his doping.
Travis Tygart appeared at a French government hearing in Paris on Thursday to discuss ways to improve the fight against doping.
After the USADA'S scathing report on systematic doping by Armstrong and his teams, he was stripped of his seven Tour de France titles and banned from elite sport for life.
Cycling body UCI has been accused of covering up suspicious samples from Armstrong, accepting financial donations from him and helping him avoid detection in doping tests. It denied those accusations in a statement Thursday.
During the French Senate hearing, Tygart said he had "evidence of the UCI's involvement in this affair," and Armstrong could hold the key to revealing the extent of that involvement.
"Armstrong led us to believe - during the course of our interaction with him - that he had evidence of their complicity in this situation, and of course we've developed additional information that will come out through our process, that I can't comment on right now," Tygart said in an interview with The Associated Press.
Tygart, who said he last spoke with Armstrong about a month ago, hopes the rider changes his mind and details what happened during his reign as cycling's undisputed superstar.
"We're hopeful at some point he'll come in and be truthful. I think he could provide a lot of information," Tygart told the AP after speaking before the Senate for about 1 1/2 hours. "We certainly are under the impression based on our conversations around our meeting back in December that he has information and evidence that would be extremely helpful and powerful in trying to set cycling on a new path."
Armstrong declined comment to the AP about Tygart's statement.
The UCI said in a statement that it "categorically rejects allegations of collusion."
"The fact is that Mr. Tygart has no evidence of any wrongdoing and has chosen to make headlines on a convenient interpretation of a conversation he had with Lance Armstrong," cycling's governing body said.
"He should establish the facts before jumping to conclusions. The UCI welcomes any assistance and clarification that Lance Armstrong may wish to give Mr. Tygart on the matter."
After years of denials, Armstrong finally confessed to doping during an interview with Oprah Winfrey in January. Tygart thinks there is still much more to come and that Armstrong has crucial information to share.
"Our firm belief is (he has) and obviously I wouldn't say that unless I had backing to say it," Tygart said. "We're convinced."
Tygart also wants the UCI to maintain its pledge - made in November when it set up an independent commission - to examine claims it had covered up suspicious samples from Armstrong and accepted financial donations from him. Two months later, the commission was disbanded.
"We're hopeful that (the UCI) are going to take decisive action and we're fully prepared to participate in a meaningful process, not a setup, a self-scripted outcome," Tygart told AP. "And if not through that, then it will be through the ongoing process that we're now involved with."
During his hearing, Tygart answered many questions concerning the UCI's alleged role in covering up Armstrong's doping.
Tygart said the UCI was clearly "aware of several (suspicious) samples" returned by Armstrong at the 2001 Tour of Switzerland and 2002 Dauphine Libere race, and the six positive EPO samples from the 1999 Tour - first reported by sports daily L'Equipe in 2005 - but had "failed to proceed on any of this data."
Tygart said the UCI "took every obvious effort to obstruct us" in the Armstrong case and should not oversee drug-testing at the Tour. He said 30 percent of samples from the 2010 Tour were not tested for the blood-booster EPO.
"There are holes in the testing that the AFLD (French Anti-Doping Agency) or USADA would never let happen," he said. "These holes give dirty athletes a runway to fly their planes through."
Former AFLD chief Pierre Bordry, often at odds with Armstrong, attended the hearing and warmly embraced Tygart.
Bordry said in January that the UCI should no longer be involved with Tour testing until it fully answers questions. The independent commission was set up to scrutinize Pat McQuaid, who was elected as UCI president weeks after Armstrong first retired in 2005, and his predecessor, Hein Verbruggen, in their relations with Armstrong.
Two months later, the UCI shut down the panel, saying it wanted a separate amnesty-style "truth and reconciliation commission" instead.
"The only decisive action they've made is to disband the independent commission right at the moment when the independent commission was finally taking off the blinders and undoing the handcuffs to truly act independent," Tygart told reporters in a separate briefing.
The UCI suggested Tygart attempted to rewrite history by ignoring that "USADA failed to catch Lance Armstrong having tested him just 29 times during his career."
"The UCI by comparison tested Armstrong 189 times," the governing body said. "And it was the UCI catching these two high-profile riders (Floyd Landis and Tyler Hamilton) which ended up with them confessing and so enabled the investigation to move against Armstrong."
Armstrong's longtime team manager, Johan Bruyneel, who helped him win all seven of his Tours, has been charged by USADA with doping violations but is fighting that case in arbitration.
But it remains unclear when the case will be heard.
"I just can't comment on the specifics of it," Tygart said. "We want to hear under oath, in the United States - where if he lied there can be consequences - we want to know, we want every question to be answered. We look forward to that opportunity (as in) in every case."