The US Anti-Doping Agency (USADA) has brought formal doping charges against US cyclist Lance Armstrong and he has been immediately banned from competition in triathlons as a result, the Washington Post reported on Wednesday.

Armstrong, a seven-time Tour de France winner, denied the charges in a statement: "I have never doped, and, unlike many of my accusers, I have competed as an endurance athlete for 25 years with no spike in performance, passed more than 500 drug tests and never failed one."

The Post cited a 15-page charging letter by the USADA.

It said the agency, which oversees anti-doping in Olympic sports in the United States, was empowered to bring charges that could lead to suspension from competition and the rescinding of awards but did not have authority to bring criminal charges.

A spokesman for the USADA was not immediately available to comment.