The judge who presided over Amanda Knox's second murder conviction said he suffered over the verdict but that he and the jury agreed about her guilt in the death of British student Meredith Kercher.
Judge Alessandro Nencini told the Italian newspaper Corriere della Sera the jury had come up with a motive that would be explained in the written explanation of the verdict, expected within three months.
A White House official has declined to comment when pressed on the possible extradition of Amanda Knox to Italy.
A spokesman said: "This is a matter, as I understand it from my reading of the press, is still in a legal proceeding.
"For questions about that issue, I would refer you, as a broad principle as opposed to a matter that is still in a legal process, I would refer you to the State Department and the Department of Justice."
John Kercher, whose daughter Meredith was killed in 2007, told ITV News that there is nothing to celebrate today: "You don't celebrate guilty - you celebrate closure and we still don't have that.
"That's all we want. We want it to end. It's been over six years and we still have another judicial process ahead now."
He added that the American media were jumping to conclusions when they say Amanda Knox could escape extradition under the double jeopardy law."They have not been tried twice so double jeopardy should not come into this."There has only been one actual trial. This was an appeal being re-done.
"Now they can take this to the Supreme Court... to say they have been tried for the same crime twice is not right."
Lawyer and legal analyst Lisa Bloom has said that there is a good chance Amanda Knox could face extradition to Italy, saying: "I think it's certainly possible...If the conviction is upheld I would expect Italy to want to extradite her, after all she's been convicted of murder there."
Amanda Knox says she is not prepared to extradited.
Speaking to ABC in America she described her shock at the guilty verdict.
Asked if she was ready to be extradited, Knox said: "I'm not. Before that even happens we have to go the Supreme Court, we have to understand the motivation behind what's happened, so I don't even know what their motivation could be. This really has hit me like a train.
"I really did not expect this to happen. I expected better from the Italian justice system. They found me innocent before, how can they say it's guilt beyond a reasonable doubt."