Andrew Mountbatten-Windsor is facing growing pressure from US officials and the family of his prominent accuser Virginia Giuffre to testify in the US about his links to paedophile financier Jeffrey Epstein.
Speaking to the BBC, Democrat Congressman Ro Khanna said the Royal Family had not been transparent, while Democrat Congresswoman Teresa Leger Fernandez said King Charles III should direct his brother to go to the US to answer questions.
Earlier on Tuesday, the King said the Royal Family were ready to support police in their inquiries.
Andrew has repeatedly denied any wrongdoing and reached an out-of-court settlement with Giuffre in 2022 containing no admission of liability.
In the King's first intervention in the latest round of revelations in the Epstein scandal, a Buckingham Palace spokesperson said if they were approached by the police, they stood ready to support them in their investigation.
It added the King had made clear...his profound concern over allegations against his brother, and the King and Queen's thoughts and sympathies have been, and remain with, the victims of any and all forms of abuse.
Thames Valley Police announced on Tuesday it was assessing a complaint by anti-monarchy group Republic over the alleged sharing of confidential material by Andrew with Epstein.
The former prince appears to have knowingly shared confidential information with Epstein from his official work as trade envoy in 2010 and 2011, according to material in the latest release of files seen by the BBC.
Andrew has been contacted for comment but is yet to respond.
When asked by the BBC if the former prince should go to the US, Khanna said that would be appropriate.
The Congressman, who co-sponsored the law that compelled the justice department to release the Epstein files last year, also said the Royal Family should come clean and lay out what they knew and what action they're going to take.
He added, They have a large wealth, they should probably be compensating these survivors for the horrors that have taken place.
Khanna said the Royal Family were finally asking for an investigation, and that these women have been denied justice.
This comes a day after Khanna told journalists this was the most vulnerable the British monarchy had been, and said stripping Andrew of a title was not enough.
The former prince has also moved out of his Windsor home and is currently living at Wood Farm on the Sandringham Estate in Norfolk while his new permanent home undergoes renovations.
Congresswoman Teresa Leger Fernandez, who is on House Oversight Committee, called for more transparency from Andrew.
She urged the King to tell his brother to answer questions here at the Oversight Committee.
She argued, You cannot say 'I am protected because I'm no longer in the jurisdiction of the United States, so I cannot be held liable'.
Sky Roberts, the brother of Virginia Giuffre, also expressed that Andrew should testify in front of Congress.
Senate Democratic leader Chuck Schumer concurred with this sentiment.
Recent emails released by the US Department of Justice reveal multiple unsuccessful attempts by US authorities for Andrew to aid in Epstein inquiries.
While the former prince cannot be compelled by a subpoena to come to the US, this limitation has provoked frustration among lawmakers. Last autumn, Democrats set a November deadline for Andrew to testify regarding his knowledge of Epstein, but he did not respond.
Since three million more documents related to Epstein were released, pressure on Andrew has intensified, with claims that a second woman was sent to the UK by Epstein for sexual encounters.
Photographs reportedly show him kneeling over a female lying on the ground, both fully dressed, included in the latest files.
Andrew continues to vehemently deny any wrongdoing, asserting that being named in the Epstein files does not imply misconduct.
