US prosecutors said on Tuesday they have no plans to press criminal charges against cycling cheat Lance Armstrong, despite his confession that he owes his Tour de France victories to illegal doping.

US attorney Andre Birotte, who led a federal investigation into the disgraced rider, did not definitively rule out action, but said Armstrong's public admission had not yet changed the decision not to prosecute.

"We made a decision on that case, I believe, a little over a year ago," he said, when asked about the status of the federal inquiry into long-standing claims that Armstrong had run a doping program and had lied to federal agents.