The International Cycling Union on Friday said it will wait for the U.S. Anti-Doping Agency to explain why Lance Armstrong should lose his unprecedented seven Tour de France titles before commenting on the case.

The news preceded a statement from USADA saying it had officially stripped Armstrong of his Tour de France titles after he dropped his fight against drug charges that threatened his legacy as one of the greatest cyclists of all time.

"Any time we have overwhelming proof of doping, our mandate is to initiate the case through the process and see it to conclusion as was done in this case," USADA CEO Travis Tygart said.

UCI, the sport's governing body, says it wants USADA to "submit to the parties concerned (Mr. Armstrong, WADA and UCI) a reasoned decision explaining the action taken."

The UCI says the World Anti-Doping Code requires USADA to do this in cases "where no hearing occurs."

Amaury Sport Organization, which runs the Tour de France, says it will wait to see what happens before commenting on Armstrong's case.

USADA also said it had issued Armstrong a lifetime ban on Friday. Under the World Anti-Doping Code, he could lose the bronze medal from the 2000 Olympics as well as any awards, event titles and cash earnings.

The UCI and USADA have engaged in a turf war over who had jurisdiction in the case.

Armstrong, who retired last year, declined to enter USADA's arbitration process -- his last option -- because he said he was weary of fighting accusations that have dogged him for years. He consistently has pointed to the hundreds of drug tests that he has passed as proof of his innocence during his extraordinary run of Tour titles from 1999 to 2005.

"There comes a point in every man's life when he has to say, 'Enough is enough.' For me, that time is now," Armstrong said in a statement sent to The Associated Press. He called the USADA investigation an "unconstitutional witch hunt."

"I have been dealing with claims that I cheated and had an unfair advantage in winning my seven Tours since 1999," he said. "The toll this has taken on my family and my work for our foundation and on me leads me to where I am today -- finished with this nonsense."

USADA reacted quickly and treated Armstrong's decision as an admission of guilt, hanging the label of drug cheat on an athlete who was a hero to thousands for overcoming life-threatening testicular cancer and for his foundation's support for cancer research.

"It is a sad day for all of us who love sport and athletes," Tygart said. "It's a heartbreaking example of win at all costs overtaking the fair and safe option. There's no success in cheating to win."