The Duke of York has been requested by the US authorities to testify about his relationship with sex offender Jeffrey Epstein, the BBC has been told.
It was first reported that the US Department of Justice had made a formal request to speak to Prince Andrew as part of its Epstein inquiry, reports the BBC citing The Sun.
He has been heavily criticised for his friendship with the US financier.
The duke has previously said he did not witness any suspicious behaviour during visits to Epstein's homes.
Prince Andrew stepped away from royal duties last year following a widely-criticised 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.
BBC royal correspondent Jonny Dymond said the BBC had confirmed the reports that the US authorities had submitted a mutual legal assistance (MLA) request to the Home Office - although this has not been confirmed by the US Department of Justice or 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.
Our correspondent said the duke's legal team was bitterly unhappy about the leaking of the request, with a source describing it as "an extraordinary breach of confidentiality".
A full statement is expected later with details about Prince Andrew's cooperation with US legal authorities.
MLA requests by other states are used to obtain assistance in an investigation or prosecution of criminal offences, generally when cooperation cannot be obtained by law enforcement agencies.
According to Home Office guidance, it is "usual policy" that the existence of a request is neither confirmed or denied.
In his interview with the BBC's Newsnight programme in November 2019, the duke said he did not regret his friendship with Epstein, despite the financier having been convicted of soliciting an underage girl for prostitution in 2008.
Shortly after it was broadcast, he said he was "willing to help any appropriate law enforcement agency".
He was criticised in January by the US prosecutor in charge of the investigation into Epstein - Geoffrey Berman - who said the prince had provided "zero co-operation" to the investigators.