(REUTERS) - The United States Anti-Doping Agency (Usada) will push ahead with efforts to clean up cycling without help from Lance Armstrong after the disgraced cyclist rejected another deadline to meet anti-doping investigators by Wednesday.
Armstrong's lawyer Tim Herman said in a statement published in USA Today that the former cyclist still had "issues" with Usada, who had exposed him as drug cheat and led to him being stripped of his seven Tour de France titles.
In a two-part television interview with Oprah Winfrey last month, Armstrong admitted to using performance-enhancing drugs throughout his career.
Following his admission, Usada offered Armstrong an opportunity to come forward and tell what he knows about doping in cycling and provide details about how he cheated and was able to avoid detection.
The anti-doping agency had originally provided Armstrong with a deadline of Feb 6 but on the cyclist's request extended that offer until Wednesday.
"Following his (Armstrong's) recent television interview, we again invited him to come in and provide honest information, and he was informed in writing by the World Anti-Doping Agency (Wada) that this was the appropriate avenue for him if he wanted to be part of the solution," Mr Tygart said in a statement.
"Over the last few weeks he has led us to believe that he wanted to come in and assist Usada, but was worried of potential criminal and civil liability if he did so.
"Today we learned from the media that Mr Armstrong is choosing not to come in and be truthful and that he will not take the opportunity to work toward righting his wrongs in sport."
Mr Tygart said the anti-doping agencies were determined to rid the sport of doping with or without Armstrong's help.
"At this time we are moving forward with our investigation without him and we will continue to work closely with Wada and other appropriate and responsible international authorities to fulfill our promise to clean athletes to protect their right to compete on a drug free playing field," he said.
Armstrong was willing to cooperate should an international tribunal be formed to address doping in professional cycling, his lawyer said.