The US Anti-Doping Agency (USADA) erased 14 years of Lance Armstrong’s career on Friday, including his record seven Tour de France titles, and banned him for life from the sport that made him the hero of millions of cancer survivors, after concluding he used banned substances.

The USADA said it expected cycling’s governing body to take similar action, but the International Cycling Union (ICU) was measured in its response, saying it first wanted a full explanation on why Armstrong should relinquish the Tour de France titles he won between 1999 and 2005.

The Amaury Sport Organization that runs the Tour de France, the world’s most prestigious cycling race, said it would not comment until hearing from the ICU and the USADA. The USADA contends that the cycling body is bound by the World Anti-Doping Code to strip Armstrong of one of the most incredible achievements in sports.

Armstrong, who retired a year ago, said on Thursday that he would no longer challenge USADA and declined to exercise his option of entering arbitration. While announcing the decision, he again denied taking banned substances during his career and called the USADA’s investigation a "witch hunt".

"Nobody wins when an athlete decides to cheat with dangerous performance-en hancing drugs, but clean athletes at every level expect those of us here on their behalf, to pursue the truth to ensure the win-at-all-cost culture does not permanently overtake fair, honest competition," said USADA chief executive Travis Tygart. "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."

Mr Tygart said the UCI was "bound to recognise our decision and impose it [the ban]". He said: "They have no choice but to strip the titles under the code."

Turf war

The ICU and USADA have engaged in a turf war over who should prosecute Armstrong. The ICU even backed Armstrong’s failed legal challenge to USADA’s authority, and it cited the same World Anti-Doping Code while saying it wanted to hear more from the American agency.

"As USADA has claimed jurisdiction in the case, the UCI expects that it will issue a reasoned decision explaining the action taken," the ICU said in a statement. It said legal procedures obliged USADA to fulfil this demand in cases "where no hearing occurs."

The International Olympic Committee said it would await the USADA's and the ICU's decisions before taking any step against Armstrong, who won a bronze medal at the 2000 Sydney Games.