U.S. Anti-Doping Agency charges Armstrong - WKOW 27: Madison, WI Breaking News, Weather and Sports

AUSTIN, Texas (WKOW) -- The U.S. Anti-Doping Agency is filing charges against seven-time Tour de France winner Lance Armstrong, questioning his victories in those storied cycling races.

Armstrong, who retired from cycling last year, could face a lifetime ban from the sport if he is found to have used performance-enhancing drugs.

The story was first reported Wednesday by the Washington Post.

The charges from USADA come just months after federal prosecutors closed a two-year criminal investigation of Armstrong without indicting him.

Armstrong maintains his innocence saying, "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."