A federal judge Friday accused special counsel Robert Mueller's team of using criminal charges to squeeze former Trump campaign chief Paul Manafort to get his help in possibly either prosecuting or impeaching President Donald Trump, multiple reports said.

The judge also strongly suggested that Mueller exceeded the scope of his special counsel office's authorization by charging Manafort with crimes that have nothing to do with Russian interference in the 2016 presidential election or possible Trump campaign collusion with Russians.

"You don't really care about Mr. Manafort's bank fraud," U.S. District Judge T.S. Ellis III said at a hearing on Manafort's case in Virginia federal court, where the trial in the case is set to begin July 10.

"You really care about what information he might give you about Mr. Trump and what might lead to his impeachment or prosecution," Ellis said.

"That's what you're really interested in," the judge added, saying Mueller's prosecutors are trying to get Manafort to "sing."

Lawyers for Manafort, who served as Trump's campaign manager for several months in 2016, were asking Ellis to dismiss bank fraud charges brought by Mueller, saying the special counsel does not have the authority to bring such charges in this case.

The indictment stems from Manafort's work consulting for a pro-Russia political party in Ukraine. Mueller also has a separate indictment pending against Manafort in federal court in Washington.

Ellis questioned why the United States attorney's office in Alexandria, Virginia, was not handling the case in federal court there, as opposed to the special counsel's office.

"I don't see how this indictment has to do with anything the special prosecutor is authorized to investigate," Ellis said.

He also told a prosecutor in Mueller's office at the hearing that he wants to see an uncensored copy of a memo that outlines the scope of the special counsel's investigation.

Special counsel attorney Michael Dreeben told Ellis that the August 2017 memo, which was written by Deputy Attorney General Rod Rosenstein, authorized Mueller's team to probe the alleged crimes by Manafort.

But Ellis said, "We don't want anyone in this country with unfettered power."