Oprah interview won't reduce sanctions against Armstrong, officials say Oprah Winfrey tells CBS that Lance Armstrong acknowledges doping The World Anti-Doping Agency calls on Armstrong to testify Legal fallout over doping accusations continues Armstrong's interview with Oprah is to air Thursday and Friday nights (CNN) -- It will take more than a television interview to reduce sanctions against Lance Armstrong, the World Anti-Doping Agency said Tuesday as Oprah Winfrey spoke out about her interview with the disgraced cyclist. "Only when Mr. Armstrong makes a full confession under oath -- and tells the anti-doping authorities all he knows about doping activities -- can any legal and proper process for him to seek any reopening or reconsideration of his lifetime ban commence," agency Director General David Howman said. Armstrong came "ready" for the interview Monday with Winfrey, the long-time TV talk show host said Tuesday. The interview will air in two parts, Thursday night and Friday night, on Winfrey's OWN cable network and the Internet, she said. Speaking with her close friend Gayle King on "CBS This Morning," Winfrey would not give specific quotes from the interview. But she appeared to confirm multiple media reports that the former seven-time Tour de France champion used the occasion to acknowledge having used performance-enhancing drugs. Asked whether she thought it was difficult for him to "come clean" to her, Winfrey responded, "Yes. I think the entire interview was difficult. Public takes shots at Armstrong in advance of Oprah interview Word of what Armstrong apparently told Winfrey is accelerating calls by anti-doping agencies for the disgraced cyclist to come clean to them about all he knows. The U.S. Anti-Doping Agency accused Armstrong in October of involvement in a sophisticated doping program while he was a professional cyclist. The world governing body for cycling, the International Cycling Union, stripped Armstrong of his seven Tour de France titles following the report. He's also been banned from the sport for life. Winfrey said the former cyclist was forthcoming in the exhausting and intense interview taped Monday in Armstrong's hometown of Austin, Texas. "We were mesmerized and riveted by some of his answers," she told CBS. While the interview was revealing, Winfrey said, his demeanor surprised her. He did not come clean in the manner that I expected. She didn't elaborate. Winfrey said her team and Armstrong's camp had originally agreed not to leak details of the interview, and that she was surprised to find that not long after the interview, news reports were saying part of what Armstrong told her had "already been confirmed." It was not immediately clear why Armstrong apparently chose to acknowledge doping after years of vigorous denials. However, he has been seeking to participate in triathlons sanctioned by U.S. Olympic authorities. Armstrong switched to that sport after retiring from cycling, but has been banned from officially sanctioned events. The World Anti-Doping Agency said Tuesday that it will take more than a television interview to reduce sanctions against Armstrong. Armstrong in talks to return Postal Service money "Only when Mr. Armstrong makes a full confession under oath -- and tells the anti-doping authorities all he knows about doping activities -- can any legal and proper process for him to seek any reopening or reconsideration of his lifetime ban commence," Howman, the agency's director general, said Tuesday. Meanwhile, fallout continued over legal wrangling concerning doping and Armstrong's involvement in the U.S. Postal Service-sponsored cycling team. A whistleblower lawsuit filed by a former teammate accuses the team's management of defrauding the government because they knew about the drug use and didn't do anything. The New York Times had reported that Armstrong was planning to testify against several powerful people in the sport of cycling who may have facilitated doping. The newspaper, citing one person close to the situation, also said he was planning to testify against officials from the International Cycling Union. But a source with knowledge of the situation denied the reports and said no settlement discussions are going on regarding the whistleblower lawsuit, which was filed by former Armstrong teammate Floyd Landis in 2010. A source familiar with the matter confirmed to CNN that lawyers for Armstrong are in discussions with the Justice Department regarding the whistleblower case. "The federal government is deciding whether to intervene in that case," the source told CNN. The Justice Department declined any comment Wednesday on potential civil action against Armstrong, saying the whistleblower suit involving claims the cycling team defrauded the government is under court seal. A spokesman for the U.S. Postal Service told CNN it could not discuss any of the legal issues associated with Armstrong and their prior relationship. CNN's Kevin Bohn contributed to this report.