Media playback is unsupported on your device Media caption Watch Oprah Winfrey talk about her interview with Lance Armstrong, courtesy of CBS This Morning

Talk show host Oprah Winfrey has said Lance Armstrong "did not come clean in the way I expected" about claims he used performance-enhancing drugs.

She did not go into details of their lengthy interview but said she had been "satisfied" with his answers.

The questions "people around the world have been waiting to hear were answered", she told CBS news.

Armstrong, who has been stripped of his seven Tour de France titles, has thus far vehemently denied dope allegations.

But rumours have been circulating for some time that he wants to come clean in order to return to professional sport, the BBC's Jane O'Brien reports from Washington.

The 41-year-old was accused last year by the US Anti-Doping Agency (Usada) of what it called "the most sophisticated, professionalised and successful doping programme" the sport had ever seen.

He is now said to be discussing whether to testify against sport officials.

'Surprising'

Ms Winfrey told CBS that the two-and-a-half hour interview in Armstrong's home town of Austin, Texas, would be broadcast over two nights, starting on Thursday.

I think the most important questions and the answers that people around the world have been waiting to hear were answered Oprah Winfrey

She said she had taken 112 questions into her interview with him, most of which she got to ask.

He was "serious and thoughtful", had prepared well for the interview, and "met the moment", she said.

"At the end of it... we both were pretty exhausted. And I would say I was satisfied," she said.

"I would say he did not come clean in the manner that I expected," she said in response to a question.

"It was surprising to me. I would say that for myself, my team, all of us in the room, we were mesmerised and riveted by some of his answers."

"I didn't get all the questions asked, but I think the most important questions and the answers that people around the world have been waiting to hear were answered," she said.

Analysis Lance Armstrong spent much of his career vehemently, and often angrily, denying doping charges. So admitting exactly the opposite would for Armstrong be less an exercise in humility than a necessary step in rebuilding his career. If he has admitted to doping, he would be able to testify to Usada about how and when he doped and who helped him - and, in doing so, perhaps lessen the lifetime ban imposed on him by the International Cycling Union. Choosing Oprah Winfrey, more a television personality than a journalist, allows Armstrong to spin his tale in the most sympathetic light possible. Her style leans more towards the redemptive confessional than the hard-hitting expose, and the cycling pro might assume he can rely a bit on the goodwill her fans have for her. For Winfrey, who has been less of a fixture in the public eye since she retired from her daytime talk show in 2011, the Armstrong interview is a coup. It's especially useful as she tries to continue the 10 months of growth she's helped orchestrate at her once flailing network.

She would leave it to others to decide whether he was contrite, she went on to say.

Ms Winfrey told CBS that she had agreed with Lance Armstrong and his team that they would not talk about what had been said until the broadcast, but rumours of a confession quickly began circulating in the US media.

"By the time I left Austin and landed in Chicago, you all had already confirmed it. So I'm like - how did you all do that? We all agreed that we weren't going to say anything," she said.

"I'm sitting here now because it's already been confirmed."

When asked why Armstrong had agreed to the interview, Ms Winfrey said: "I think he was just ready."

'Legal issues'

The interview was recorded just hours after Armstrong apologised to staff at the Livestrong Foundation but stopped short of a full admission of guilt.

Armstrong was stripped of his seven Tour de France titles, lost most of his sponsorships and was forced to leave Livestrong after the damning Usada report.

Admitting doping might be a first step into trying to mitigate his lifetime ban from competition. He is also said to be planning to testify against powerful individuals in the world of cycling - though not other cyclists - he will claim knew about or facilitated the doping, sources said.

But an admission of guilt would raise legal issues as well as further backlash from the cycling world and cancer community, in which Armstrong is a prominent figure as a cancer survivor.

Media playback is unsupported on your device Media caption Cooke attacks cycling drug cheats

The New York Times has reported Armstrong's supporters are concerned he could face perjury charges if he confesses to using performance-enhancing drugs, because he testified in a 2005 court case that he had never done so.

Former teammate Floyd Landis - who was stripped of his 2006 Tour de France title for doping - has filed a federal whistleblower lawsuit accusing Armstrong of defrauding the US Postal Service, which sponsored the team to the tune of more than $30m (£18.7m).

The US Department of Justice is considering whether to join the lawsuit against him, reports say, and Armstrong's lawyers are said to be in negotiations to settle the suit.

The UK's Sunday Times is already suing Armstrong for up to $1.6m over a libel payment to him in 2004 after the newspaper alleged he had cheated.

And a Texan insurance company is pursuing Armstrong for $11m over insured performance bonuses paid to the American after he claimed his fourth, fifth and sixth Tour de France victories.