London - Buckingham Palace issued a new denial on Sunday of allegations that a US woman was kept as an underage "sex slave" and forced to have sexual relations with Britain's Prince Andrew.The woman, identified in legal documents only as "Jane Doe #3," has alleged in a US court filing that she had been kept as a "sex slave" by Wall Street financier Jeffrey Epstein, a friend of the prince.Prominent US attorney Alan Dershowitz, Epstein's lawyer, was also named in the court papers. Both he and Andrew, the Duke of York, who is fifth in line to the throne, have vigorously denied the allegations.In a strongly-worded response on Friday, Buckingham Palace said that "any suggestion of impropriety with underage minors is categorically untrue".But the palace took the unusual step of issuing a second statement after British Sunday newspapers printed details of interviews the plaintiff has given in recent years."It is emphatically denied that the Duke of York had any form of sexual contact or relationship" with the woman, the palace said."The allegations made are false and without any foundation."The Mail on Sunday and the Sunday Mirror newspapers both published details of interviews given by the woman in recent years, in which she discusses three alleged encounters with Andrew.Meanwhile, British press reported that the prince had flown back into Britain after taking a ski trip to Switzerland.'Made up'According to the motion filed in a Florida court this week, the woman alleges she was "forced to have sexual relations" with 54-year-old Andrew, meeting him in London, New York and the Caribbean at Epstein's behest.Epstein, a known friend of Queen Elizabeth II's second son, was convicted in 2008 of soliciting an underage girl for prostitution and served a prison term.Dershowitz, whom "Jane Doe #3" was allegedly forced to have sex with on several occasions, told AFP the story was "made up".In a new interview with the BBC, the Harvard Law School professor said he wanted the plaintiff to speak under oath in court."I unequivocally and without any reservations totally deny all the allegations about sexual contact," he said."My goal is to bring charges against the client and require her to speak in court. If she believes she has been hurt by me and by Prince Andrew, she should be suing us for damages."I welcome any opportunity which would put her under oath and require her to state under oath these false allegations.""What they've done was so underhanded: simply asserting it in a legal proceeding, not asking for any opportunity to prove it, not alleging that they could prove it, not giving me an opportunity to disprove it. That's Kafkaesque."He said Epstein was "very upset at these lies being circulated".Epstein links cost Andrew jobSpeaking of the denial of her claims, "Jane Doe #3" told The Guardian newspaper: "I'm not going to be bullied back into silence."But Dershowitz, who said he did not recognise her name or picture, countered: "I would like the opposite: I want her to speak!"I challenge her to repeat her statement... under oath."The woman claimed she was Epstein's sex slave from 1999 through to 2002.In 1960 Andrew became the first child born to a reigning British monarch in more than a century. His elder brother Charles, the heir to the throne, was born before their mother Elizabeth became queen in 1952.He was Britain's special representative for international trade and investment, a roving business ambassador, for 10 years.But the prince gave up the post in 2011 following intense scrutiny over his relationship with Epstein, candid comments recorded in US diplomatic cables exposed by WikiLeaks, and links with key figures in repressive regimes.The naval officer, who flew helicopters in the 1982 Falklands War, remains close to his ex-wife Sarah, with whom he has two daughters, Princesses Beatrice and Eugenie.The filing in which Andrew is named is to be included in an ongoing civil case that accuses federal prosecutors of cutting a plea-bargain deal with Epstein without consulting his victims, in violation of the US Crime Victims Rights' Act.Meanwhile, Britain's Metropolitan Police revealed it had not received any complaint related to the case but would investigate any allegations.