The Duke of York's lawyers have rejected claims by US prosecutors that he has not co-operated with the inquiry into sex offender Jeffrey Epstein, insisting he has offered to help.
In a statement, Prince Andrew's legal team said he offered help on "at least three occasions".
The lawyers suggested the US Department of Justice was seeking publicity rather than accepting the offer of help.
However, the US prosecutors hit back within hours.
Geoffrey Berman, US Attorney for the Southern District of New York, said Prince Andrew had "yet again sought to falsely portray himself to the public as eager and willing to co-operate" with the investigation into sex trafficking by Jeffrey Epstein and his associates,.
However, he said, the prince "has not given an interview to federal authorities, has repeatedly declined our request to schedule such an interview, and nearly four months ago informed us unequivocally - through the very same counsel who issued today's release - that he would not come in for such an interview".
He added: "If Prince Andrew is, in fact, serious about co-operating with the ongoing federal investigation, our doors remain open, and we await word of when we should expect him."
The duke's lawyers declined to comment further, but a source said: "This is the third time Berman has breached his own confidentiality rules, further diminishing our trust in the DoJ's willingness to play a straight bat. It's frankly bewildering."
The duke stepped away from royal duties last year following his widely-criticised comments in a BBC interview about his relationship with Epstein, who took his own life in a US jail cell in August, aged 66, while awaiting trial on sex trafficking and conspiracy charges.
The duke has been heavily scrutinised for his friendship with Epstein, but he has said he did not witness any suspicious behaviour during visits to the US financier's homes.
Shortly after the interview was broadcast, Prince Andrew said he was "willing to help any appropriate law enforcement agency" with their investigations.
But in late January, Mr Berman claimed that the prince had provided "zero co-operation", and in March he said Andrew had "completely shut the door" on helping investigators.
In a statement on Monday, Prince Andrew's legal team said: "The Duke of York has on at least three occasions this year offered his assistance as a witness to the US Department of Justice".
"Unfortunately, the DoJ has reacted to the first two offers by breaching their own confidentiality rules and claiming that the duke has offered zero co-operation. In doing so, they are perhaps seeking publicity rather than accepting the assistance proffered."
Earlier in the day, it was revealed the DoJ had made a formal request to speak to the prince as part of its Epstein inquiry, by submitting a mutual legal assistance (MLA) request to the UK Home Office.
Under the terms of a MLA request if Prince Andrew does not voluntarily respond, he can be called to a UK court to answer questions.
The duke's lawyers described the request as "disappointing" because the Duke of York was "not a target of the DoJ investigation and has recently repeated his willingness to provide a witness statement".
The charges against Jeffrey Epstein
Allegations against Jeffrey Epstein started surfacing in 2005 when the parents of a 14-year-old girl told police in Florida that Epstein had molested their daughter at his Palm Beach home.
The financier was accused of paying girls under the age of 18 to perform sex acts at his Manhattan and Florida mansions between 2002 and 2005.
However, a controversial secret plea deal in 2008 saw him plead guilty to a lesser charge of soliciting a minor for prostitution.
He received an 18-month prison sentence and was released on probation after 13 months.
In July 2019 he was charged in New York with further allegations of sex trafficking and conspiracy and was due to face trial. He pleaded not guilty to all the charges.
The duke's lawyers, Clare Montgomery QC and Stephen Ferguson, said they had previously chosen not to make any comment about their dealings with the DoJ but had now released a "clarifying" statement "in view of misleading media briefings".
Wronged. That's the word that sums up this icily angry statement from Prince Andrew's lawyers.
They kept their silence as the US Attorney for the Southern District of New York, Geoffrey S Berman, paraded on the steps of Epstein's former New York City mansion and flung about what they say are lies about the duke.
They believed the US Department of Justice when it told them that confidentiality would be respected; then they saw it flouted.
The lawyers heard the Department of Justice when it said Prince Andrew was not, and never had been, a target of the investigation; and then a well-placed leak told the world that the US was trying to drag the duke to court.
In the cool language of lawyers, they are mightily upset on behalf of their client; perhaps, they ask, the department is seeking publicity rather than the assistance proffered? The leaks have presented they say an "entirely misleading" version of the relationship between them and the US authorities.
Up until this point the duke has only been spoken for by so-called friends dripping poison into the ears of friendly journalists. But this is different. The lawyers think their client has been wronged, and they are not shy of telling the world about it.
The prince's lawyers added that the first time US authorities requested the duke's help was on 2 January. They were advised the duke "is not and has never been a target of their criminal investigations into Epstein" and they wanted his "confidential, voluntary co-operation".
The statement added that they were given "an unequivocal assurance that our discussions and the interview process would remain confidential".
It was a "matter of regret" that the DoJ had breached its own rules of confidentiality, the lawyers said, "as they are designed to encourage witness cooperation".
"Far from our client acting above the law, as has been implied by press briefings in the US, he is being treated by a lower standard than might reasonably be expected for any other citizen," they said.
In his interview with the BBC's Newsnight programme in November 2019, the duke also said he did not regret his friendship with Epstein - which led to Epstein attending events at Windsor Castle and Sandringham - because it had "some seriously beneficial outcomes".
However, he admitted it was wrong of him to visit Epstein at his home in 2010, after his conviction.
He also denied having sex with Virginia Giuffre, when she was a teenager, who said she was trafficked by Epstein when she was 17 and forced to have sex with Prince Andrew.
Prince Andrew emphatically denies any form of sexual contact or relationship with her and says any claim to the contrary is false and without foundation.
He said he has no recollection of ever meeting the woman, who was previously known as Virginia Roberts.