The sport's governing body said Friday it expects USADA to submit documents "to the parties concerned," as the case threatens to wipe a cycling icon almost out of the record books.
"The UCI recognizes that USADA is reported as saying that it will strip Mr. Armstrong of all results from 1998 onwards in addition to imposing a lifetime ban from participating in any sport which recognizes the World Anti-Doping Code," the Switzerland-based organization said in a statement.
"As USADA has claimed jurisdiction in the case the UCI expects that it will issue a reasoned decision" explaining the action taken, the UCI said, adding that legal procedures obliged USADA to fulfil this demand in cases "where no hearing occurs."
Armstrong has chosen not to pursue an arbitration hearing where he could have fought charges brought by U.S. anti-doping officials that his teams doped when he won the Tour from 1999-2005.
The UCI and USADA have engaged in a turf war over who should prosecute allegations against Armstrong.
Armstrong disputes that USADA has power to re-write cycling results, and uncertainty remains over what role the ASO sports promotion company which organizes the Tour de France will have in the process.
Armstrong insisted his decision to decline arbitration was not an admission of guilt, but a refusal to enter a process he believes is unfair.
"Lance has never withdrawn from a fair fight in his life so his decision today underlines what an unjust process this has been," Johan Bruyneel, Armstrong's longtime coach, wrote on his personal website on Friday.
Still, USADA chief executive Travis Tygart said the UCI was "bound to recognize our decision and impose it" as a signatory to the World Anti-Doping Code.
USADA maintains that Armstrong used banned substances as far back as 1996, including the blood-booster EPO and steroids, as well as blood transfusions.
The agency also claims to have blood tests from 2009 and 2010 which were "fully consistent" with doping, at a time when Armstrong was monitored by the biological passport program run by the UCI.
USADA wants to annul all Armstrong's race results from August 1998. At the 2000 Sydney Olympics, he won a bronze medal in the road time trial.
The International Olympic Committee said Friday it will await decisions by the U.S. agency and UCI before taking any steps against the rider.
Even if Armstrong loses the legal battle, the UCI would still be able to regard him as its 1993 world champion in the men's road race in Oslo, Norway.