The United States Anti-Doping Agency has called on Lance Armstrong to admit to the full extent of his use of performance-enhancing drugs under oath following the disgraced cyclist's televised confession.
After years of denials, the 41-year-old American told Oprah Winfrey that he doped during his run of seven successive Tour de France titles, from 1999 to 2005. The confession followed a USADA investigation which implicated Armstrong as a central figure in what it called "the most sophisticated, professionalised and successful doping programme that sport has ever seen".
Following the broadcast of the interview, USADA chief executive Travis Tygart said in a statement: "Tonight, Lance Armstrong finally acknowledged that his cycling career was built on a powerful combination of doping and deceit. His admission that he doped throughout his career is a small step in the right direction."
He added: "But if he is sincere in his desire to correct his past mistakes, he will testify under oath about the full extent of his doping activities."
Armstrong stood down as chairman of the Lance Armstrong Foundation, known as Livestrong, as pressure increased following the publication of USADA's reasoned decision into the doping practices of him and his United States Postal Service team.
"We at the Livestrong Foundation are disappointed by the news that Lance Armstrong misled people during and after his cycling career, including us," a statement from the charity read. "Earlier this week, Lance apologised to our staff and we accepted his apology in order to move on and chart a strong, independent course.
"We look forward to devoting our full energy to our mission of helping people not only fight and survive cancer, but also thrive in life after cancer.
"Even in the wake of our disappointment, we also express our gratitude to Lance as a survivor for the drive, devotion and spirit he brought to serving cancer patients and the entire cancer community.
"Lance is no longer on the foundation's board, but he is our founder and we will always be grateful to him for creating and helping to build a foundation that has served millions struggling with cancer.
"Our success has never been based on one person - it's based on the patients and survivors we serve every day, who approach a cancer diagnosis with hope, courage and perseverance. They have been, are and always will be our focus."