London, Feb 23 : The U. S. government would join a doping lawsuit filed by one of Lance Armstrong''s former team-mates Floyd Landis alleging that the shamed cyclist defrauded government sponsors while he was in the US Postal team.

An American daily has reported that the Justice Department filed papers in a federal court on Friday to join the lawsuit filed by d Landis, himself an admitted dope cheat who lost the 2006 Tour de France crown because of doping.

Meanwhile Armstrong''s attorney Robert Luskin said the American cyclist and his representatives worked constructively over these last weeks with federal lawyers to resolve this case fairly, but those talks failed because theu disagree about whether the Postal Service was damaged.

Another American daily reported that the lawsuit was based on the False Claims Act, which allows citizens to sue for alleged fraud against the government and receive as much as a third of any money recovered. The law would allow the plaintiffs to recover as much as triple the amount of the 1999 to 2004 sponsorship, which was worth an estimated 30 million dollars, the Telegraph reports, the paper reported.

Armstrong admitted to Oprah Winfrey last month that he used performance-enhancing drugs during his record seven Tour de France championships from 1999-2005, the paper added. All seven titles were stripped from him last year after a report by the US Anti-Doping Agency (USADA), which accused the cyclist of taking part in one of the biggest cheating operations in sports history.

On Wednesday, Armstrong said that he would not cooperate with a USADA probe into dope cheats in cycling but would be willing to help other anti-doping inquiries. (ANI)