• Federal prosecutors said "the mere fact" that Rudy Giuliani is a lawyer — one who represented former President Donald Trump — does not mean he is "immune to a criminal investigation."
• Their filing pushed back on efforts by Giuliani's attorneys to attack the legality of search warrants for his iCloud account in 2019 and for the former New York City mayor's Manhattan home and office last month.
• Giuliani is under criminal investigation for his dealings in Ukraine.

Federal prosecutors said in a court filing Friday that "the mere fact" that Rudy Giuliani is a lawyer — one who represented former President Donald Trump — does not meant he is "above the law or immune to a criminal investigation."

The filing pushed back on efforts by Giuliani's attorneys to attack the legality of search warrants for his iCloud account in 2019 and for his Manhattan home and office last month, which were issued as part of an ongoing criminal probe into his activities in and related to Ukraine.

Eighteen electronic devices belonging to New York's former mayor and to employees of Giuliani Partners were seized in late April as part of those warrants.

Giuliani's lawyers argue that the search of his iCloud — which was not known to Giuliani for about 18 months — may have violated his attorney-client privilege and the right of Trump as president to have his communications with his lawyer protected.

And they say the recent search warrants may be tainted by their reliance on information obtained from the iCloud search.

Another well-known Republican lawyer, Victoria Toensing, was the subject of similar search warrants.

"The warrants authorizing the searches of those devices were issued by a United States District Judge — this Court — on a finding that there was probable cause to believe that those devices contained evidence, fruits, and instrumentalities of specified federal crimes," prosecutors from the office of the U.S. Attorney for the Southern District of New York wrote in their new filing in Manhattan federal court.

Prosecutors said the search of devices and electronic accounts belonging to attorneys such as Giuliani and Toensing "requires special care in order to protect the confidentiality of attorney-client communications that may be found in search materials."

To that end, prosecutors said they have "gone above and beyond those obligations" by asking a judge to appoint a so-called special master to review the recently seized materials for potentially privileged material, which then would be kept from investigators who are conducting the criminal probe of Giuliani.

Prosecutors said a so-called filter team served that purpose in reviewing the 2019 warrants for his and Toensing's iCloud accounts.

"But, to be clear, the mere fact that Giuliani and Toensing are lawyers does not mean that they are above the law or immune to criminal investigation," prosecutors wrote.

"Yet that is effectively what Giuliani and Toensing argue in their motions: because they are lawyers, the execution of search warrants, upon them was illegal and inappropriate, and as such they are entitled to the extraordinary and unprecedented remedy of converting lawfully-issued search warrants into subpoenas, so that they can review their own materials and decide what the Government gets to see. That is not the law, and their requests otherwise should be denied," the filing said.

Prosecutors argued in the filing that a judge should deny requests by Giuliani and Toensing to unseal the affidavits filed to obtain the warrants.

Giuliani's lawyer, Arthur Aidala, pushed back against the prosecutors' filing.

"In the government's submission, they allude to the fact that Mr. Giuliani is arguing he is above the law," Aidala wrote in a text message to CNBC.

"No one is saying Mayor Giuliani is above the law," Aidala wrote.

"However, the government is obligated to follow the specific procedures that must be adhered to when reviewing material obtained from a lawyer by means of a search warrant as opposed to issuing a subpoena."

Aidala added: "Any lawyer has an attorney-client privilege that he must protect on behalf of his clients."

"That privilege is doubly enhanced when the lawyer's client is the President of the United States who also enjoys Executive privilege," Aidala said.

Giuliani played a key role in trying to dig up damaging information about President Joe Biden and his son Hunter related to the latter's business dealings in Ukraine. At the time, Biden was gearing up to run for president and was widely considered to be Trump's most viable Democratic challenger.