A US prosecutor who investigated allies of President Donald Trump insisted Friday he had no intention of quitting after the attorney general issued a press release announcing his resignation.

Geoffrey Berman oversaw the prosecution of former Trump lawyer Michael Cohen and probed advisor Rudy Giuliani's efforts to discredit the president's political opponents since he was appointed to head the powerful Southern District of New York attorney's office in 2018.

He also investigated two associates of Giuliani accused of campaign finance violations and helping dig up dirt on Trump's election challenger Joe Biden, which became the subject of an impeachment inquiry into the president.

Attorney General William Barr announced Berman's resignation late on Friday and said Trump would nominate Securities and Exchange Commission chief Jay Clayton as his replacement.

"I thank Geoffrey Berman, who is stepping down after two-and-a-half years of service as United States Attorney for the Southern District of New York," Barr said.

But Berman said he first learned of his apparent departure from Barr's press release.

"I have not resigned, and have no intention of resigning," Berman wrote.

"I will step down when a presidentially appointed nominee is confirmed by the Senate. Until then, our investigations will move forward without interruption."

Powerful New York Southern District attorney Geoffrey Berman, who prosecuted Trump's former lawyer, says he has no intention of quitting after learning Attorney General William Barr had announced his resignation in a press release
Powerful New York Southern District attorney Geoffrey Berman, who prosecuted Trump's former lawyer, says he has no intention of quitting after learning Attorney General William Barr had announced his resignation in a press release AFP / Johannes EISELE

Top Senate Democrat Chuck Schumer expressed concern over the attempt to fire Berman.

"This late Friday night dismissal reeks of potential corruption of the legal process," he said in a statement.

"What is angering President Trump? A previous action by this U.S. Attorney or one that is ongoing?"

The Trump administration has fired several officials tasked with government oversight.

State Department inspector general Steve Linick was removed from his position last month after running a misconduct probe into Washington's top diplomat and steadfast Trump ally Mike Pompeo.

Berman's predecessor in the attorney's office, Preet Bharara, was sacked after he refused Trump's demand for his resignation.

"Why does a president get rid of his own hand-picked US Attorney in SDNY on a Friday night, less than 5 months before the election?" Bharara tweeted.

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