A top US prosecutor investigating Jeffrey Epstein and his links to the Duke of York has insisted he is not resigning after the US Department of Justice announced he was “stepping down”.

Geoffrey Berman, who has also overseen prosecutions of key allies of President Donald Trump, said he learned of his apparent withdrawal as US attorney for the Southern District of New York in a press release issued on Friday night.

He said in a statement on Twitter: “I have not resigned and have no intention of resigning … I will step down when a presidentially appointed nominee is confirmed by the Senate.

“Until then, our investigations will move forward without delay or interruption.

“I cherish every day that I work with the men and women of this office to pursue justice without fear or favour – and intend to ensure that this office’s important cases continue unimpeded.”

Mr Berman’s office has prosecuted a number of associates of Mr Trump, including his former lawyer Michael Cohen, who was jailed for lying to Congress and campaign finance violations.

His office is also conducting investigations into the president’s personal lawyer Rudy Giuliani.

Senate Democratic leader Chuck Schumer tweeted: “This late Friday night dismissal reeks of potential corruption of the legal process.

“What is angering President Trump? A previous action by this US Attorney or one that is ongoing?”

Mr Berman is also at the centre of a row between the Duke of York and American authorities over his availability to answer questions about Epstein, and has accused Andrew of “shutting the door” on the probe into the child sex offender.

Mr Berman also claimed Andrew is attempting to “falsely portray himself to the public as eager and willing to co-operate” in the investigation into his former friend.

The duke’s legal team said earlier this month Andrew had made three offers to give a witness statement, and a royal source described Mr Berman’s comments as “frankly bewildering”.

US attorney general William Barr announced Mr Berman was “stepping down” after two-and-a-half years in the role in a US Department of Justice press release on Friday.

It said: “With tenacity and savvy, Geoff has done an excellent job leading one of our nation’s most significant US Attorney’s Offices, achieving many successes on consequential civil and criminal matters.

“I appreciate his service to the Department of Justice and our nation, and I wish him well in the future.”

Jay Clayton, the current chairman of the Securities and Exchange Commission, has accepted Mr Trump’s nomination for the role, which is currently being considered by the Senate, the statement added.

The duke’s legal team said in its statement: “The Duke of York has on at least three occasions this year offered his assistance as a witness to the DOJ ((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.”