WASHINGTON – The Justice Department joined a lawsuit Friday against disgraced cyclist Lance Armstrong that alleges the former seven-time Tour de France champion concealed his use of performance-enhancing drugs and defrauded his longtime sponsor, the U.S. Postal Service.

The lawsuit alleges that riders on the postal service-sponsored team, including Armstrong, knowingly violated their postal service agreements by regularly using banned substances and methods to enhance their performance.

“Lance Armstrong and his cycling team took more than $30 million from the U.S. Postal Service based on their contractual promise to play fair and abide by the rules – including the rules against doping,” said U.S. Attorney Ronald Machen, whose office is handling the case. “The Postal Service has now seen its sponsorship unfairly associated with what has been described as ‘the most sophisticated, professionalized and successful doping program that sport has ever seen.’ ”