Lance Armstrong's legal woes just became a little bigger. On Friday, the U.S. Department of Justice announced it has joined the whistle-blower lawsuit against the disgraced athlete.

The civil lawsuit, initially filed by former Armstrong teammate Floyd Landis, alleges that Armstrong and former team managers defrauded the U.S. Postal Service through their use of performance-enhancing drugs. Armstrong confessed to using steroids in a two part interview with Oprah last month. Now, the federal government wants to get back the millions of dollars the USPS paid to sponsor Armstrong’s cycling team from 1996 to 2004.

Armstrong's lawyer Robert Luskin says the once-legendary athlete has worked to resolve the issue with the feds, but couldn't come to an agreement over the USPS damages. Luskin explains, "The Postal Service's own studies show that the service benefited tremendously from its sponsorship -- benefits totaling more than $100 million." However, the feds say with the current economic climate, they’re in no position to let anyone walk away with such a large sum of money illegally.

Read more: Feds join whistle-blower lawsuit against Lance Armstrong