Lance Armstrong is being sued for more than $US1.5 million ($A1.44 million) by a British newspaper which lost a libel action for publishing doping allegations against the now-disgraced cyclist.
The Sunday Times paid Armstrong £300,000 ($A470,000) in 2006 to settle a case after it reprinted claims from a book in 2004 that he took performance-enhancing drugs.
But this year, the US Anti-Doping Agency found that Armstrong led a massive doping program on his teams. The American was stripped of his seven Tour de France titles and banned from cycling for life.
The Sunday Times announced in an article in its latest edition that it has issued legal papers against Armstrong.
"It is clear that the proceedings were baseless and fraudulent," the paper said in a letter to Armstrong's lawyers. "Your representations that you had never taken performance enhancing drugs were deliberately false."
The paper, which is owned by Rupert Murdoch's News Corporation, said its total claim against Armstrong was "likely to exceed" £1 million ($A1.56 million).
"The Sunday Times is now demanding a return of the settlement payment plus interest, as well as its costs in defending the case," the paper said.