A judge on Tuesday sharply criticized federal prosecutors for failing to get judicial approval before filing a new criminal complaint against two ex-FBI officials accused of lying to Congress about investigations of Hunter Biden.

Magistrate Judge Zia Faruqui said he would not sign off on the new complaint, which added a charge of obstruction against Nikki Floris and Bradley Benavides in U.S. District Court in Washington, D.C.

"I am not going to bless it as a superseding complaint," Faruqui said at a court hearing.

He told prosecutors that if they wanted to file a superseding complaint, a judge would have to make a finding of probable cause that a crime had been committed by the defendants first, as opposed to sending him the complaint in the middle of the night, and expecting him to sign off on it.

The judge said he did not believe that federal prosecutors had ever previously sought to file a criminal complaint without a judge's signature.

"I'm concerned with your view as to what the law is," the judge told the prosecutors. "Why today, on this one case, have you changed the entire history of how you charge cases?"

The superseding complaint that prosecutors in the office of D.C. U.S. Attorney Jeanine Pirro filed early Tuesday in court contained a signature block with Faruqui's name typed out. But the judge had not personally signed above his name.

The filing came hours before prosecutors and lawyers for Floris and Benavides were scheduled to appear before Faruqui for a preliminary hearing on the original criminal complaint, unsealed last Friday, which accuses them of making false statements to the House Judiciary Committee in 2023 about their involvement in investigations of Hunter Biden, the son of former President Joe Biden.

Floris and Benavides were arrested Friday and have been released.

The new superseding complaint sought to charge them with obstruction and attempted obstruction of a congressional proceeding.

Floris' lawyers quickly filed a motion asking Faruqui to strike the superseding complaint, arguing it is legally deficient and filed in bad faith.

Typically, criminal cases for conduct that occurred well in the past, as this one alleges, are lodged through a grand jury indictment.

A criminal complaint, which does not require a grand jury's approval and can therefore be filed much faster, is often used to establish probable cause to get an arrest warrant in situations where prosecutors need to move quickly.

"In the middle of the night, the government filed an unsigned and unsworn complaint attempting to fix the issues with their original charge against Ms. Floris and adding a new charge just as meritless as the first one," Floris' lawyers wrote in an emailed statement to CNBC on Tuesday morning.

"In our combined decades of DOJ service, we have never seen or even heard of something like this being filed. That's because the public lodging of criminal charges must be authorized by the grand jury, a judge, or the defendant herself," they wrote.

"Here, the government has taken that power for itself in a desperate attempt to delay our client's right to challenge the charges in court and litigate this case in the media, rather than the courtroom," they said.

"We have asked to address this outrageous government conduct against a decorated public servant at today's court hearing," Floris' legal team wrote.

In their motion to strike the superseding criminal complaint, the lawyers argued that the document "represents a serious abuse of the criminal charging process, a troubling disregard for the judicial safeguards governing the initiation of criminal proceedings, and a calculated effort to evade judicial scrutiny and shield the government's allegations from adversarial testing at the scheduled preliminary hearing."