Prince Andrew is cited in classified US diplomatic documents for making "inappropriate remarks", The Guardian newspaper reported on Monday, citing data released by whistle-blowing website WikiLeaks.
The documents refer to "inappropriate remarks by Prince Andrew about a UK law enforcement agency and a foreign country", The Guardian said, although it has yet to give further details on what exactly the royal said.
Buckingham Palace declined to comment but a palace source told The Daily Mail newspaper: "We are awaiting further detail, as everyone is."
Prince Andrew, Queen Elizabeth II's second son and fourth in line to the British throne, has been an unpaid trade envoy for the British government since 2001 and the job has taken him around the world.
This is not the first time the prince, known as "Airmiles Andy" for his frequent use of private jets, has courted controversy.
He has come under fire for using a villa in Abu Dhabi belonging to the Gulf state's crown prince, and the media have questioned his ties to a Kazakh billionaire who bought his British home for well over the asking price.
The Guardian was one of several newspapers worldwide given prior access to more than 250,000 US embassy files released by WikiLeaks late on Sunday.
The paper has promised to release further details, including those offering "embarrassing" assessments of Prime Minister David Cameron when he was the opposition leader before May's election, and of "weak" ex-premier Gordon Brown.