Johannesburg - Any discussion on a reduction of fallen cycling star Lance Armstrong's lifetime ban is "premature" and "speculative" until he offers information about doping, the US Anti-Doping Agency (USADA) chief said on Wednesday.
"Technically it's a possibility for him to receive a reduction," USADA CEO Travis Tygart said on the sidelines of the World Conference on Doping in Sport.
But suggestions that Armstrong's 2012 lifetime ban from competitive sport can be lifted were "premature" and "speculative", said Tygart.
International cycling's world governing body the International Cycling Union (UCI) stripped Armstrong of his seven Tour de France titles -- won between 1999 and 2005 -- in August last year, after USADA banned him for life for using a banned performance-enhancer.
The cyclist has said he would cooperate to discover the extent of doping in the sport so long as he's treated the same as his fellow drug cheats.
Punishment for other cyclists has been less severe after they admitted to doping.
Tygart welcomed the cyclist's willingness to talk, but said the effect would not be the same.
"The value is diminished significantly to some extent. He had the opportunity which he didn't take," said Tygart.
Armstrong "was the only athlete who refused to come," when USADA invited cyclists to talk about doping in June 2012.
The organisation was still "hopeful he might give information" which would be "helpful to give cycling a chance to unshackle from its past," said the US anti-doping chief.
Meanwhile UCI president Brian Cookson said a "truth and reconciliation commission" after the Armstrong scandal should be up and running early next year.
"I'm hoping to make an announcement in a couple of weeks and I'm hoping that the whole thing will be up and running early in the new year," Cookson told AFP.
Cookson met with the World Anti-Doping Agency (WADA) chiefs on the sidelines of the conference to iron out final arrangements about the commission of inquiry.
"We are very anxious that we agree those terms and conditions with WADA. We're pretty close to agreement now," he said.
Both Cookson and WADA outgoing president John Fahey said any reconsideration of Armstrong's sanctions should come from USADA, though Fahey said it would take "a miracle" to happen.
"He's been sanctioned by the United States anti-doping agencies and the penalties he got from that have been accepted by the UCI and by the wider sporting world," said Cookson.
"And really it's in the hands of the United States Anti-Doping Agency whether they would look at any reduction in that for any further information that he might volunteer."
Cookson was frank about the past "culture of doping in professional road cycling in particular" and his commitment to clean it up.
Athletes should be able to "go all of the way to the top of the sport without having to take risks, without having to cheat, without having to lie and without having to spend the rest of their lives looking over their shoulders," he said.
"I think it's cleaner now than it's been for many many years," he added.
WADA president Fahey welcomed stronger relations with the UCI under Cookson after "some rocky moments in the past".
The two leaders had "productive, constructive, progressive" discussions at the anti-doping conference, Fahey told media.
"I can assure you that WADA's support will be given to the UCI," he said, stressing that the planned commission would be "UCI's inquiry".