A federal judge on Monday sharply criticized the U.S.-based attorney for a Russian company indicted in special counsel Robert S. Mueller III’s investigation, and the attorney fired back that the judge showed “bias” against him.

The fiery exchange threatens to complicate the already complex prosecution of Concord Management and Consulting, which was indicted in February along with its owner, Russian businessman Yevgeniy Prigozhin, and other Russian individuals and companies. They are accused of financing and overseeing a social media operation to disrupt the 2016 U.S. election.

Concord’s defense team had asked a court to rule on its demand to share with Prigozhin — known as “Putin’s chef” because of his close ties to Russian president Vladi­mir Putin — millions of pages of evidence turned over by Mueller prosecutors. Under a court protective order, sensitive evidence in the case must be reviewed first by a U.S. government “firewall” counsel before being released to any non-U.S. national, including co-defendant Prigozhin, in part because of his alleged ties to Russian intelligence.

U.S. District Judge Dabney L. Friedrich of the District, who was appointed by President Trump, began a Monday hearing by lambasting defense attorney Eric A. Dubelier, saying, “I find your recent filings . . . unprofessional, inappropriate and ineffective.” The judge said Dubelier had made “meritless” attacks on Mueller, his team, other U.S. prosecutors and federal law enforcement.

Friedrich cited Dubelier’s inclusions of “what you clearly believe to be clever” references in his legal filings to “movies, cartoons and books” — ranging from the movie “Animal House” to a pre-World War II Swiss travelogue — before concluding: “I’ll say it plain and simple. Knock it off.”

When he had the chance to speak, Dubelier, a former federal prosecutor who has clashed repeatedly with Mueller prosecutors in the case, turned on Friedrich, saying that he was not prepared to address all the judge’s questions at this point but needed to consult with Concord to determine if the client continued to want his representation given her comments.

“There seems to be some bias against me by the court,” Dubelier alleged, voice rising.

Dubelier responded to the claim that he acted “unprofessionally,” saying, “Your honor, that’s your opinion,” adding, “I’ve been telling the truth.”

Shortly after, Friedrich cleared the courtroom for what she previously said would be a sealed hearing over another of Concord’s motions.

The courtroom theatrics came in a case already bogged down in legal and political maneuvering, all overseen by Friedrich, who took the bench in December 2017.

A no-nonsense former federal prosecutor, Senate Judiciary Committee staffer and member of the U.S. Sentencing Commission, Friedrich has moved on more than one occasion to rein in the witty but fiery Dubelier, who punctuated a May hearing in the case by accusing Mueller prosecutor Jeannie Rhee of lying, and by cursing loudly in the courtroom after speaking with her.

Concord has pleaded not guilty to an indictment charging it, 13 Russian individuals and two other companies including the Internet Research Agency of St. Petersburg, with conspiracy in an online effort to trick Americans into following and promoting Russian-fed propaganda that pushed 2016 voters toward then-candidate Donald Trump and away from Democratic rival Hillary Clinton.

Concord is the sole defendant to appear in court in the indictment of Russian entities under Mueller.

In a ruling last year, Friedrich agreed that prosecutors had provided “ample good cause” that sharing sensitive case materials could imperil ongoing U.S. national security investigations.

Concord’s attorneys said at the time that it was critical that their defense strategy include Prigozhin, invoking their constitutional rights to a fair trial.

But the U.S. government team — which also includes prosecutors with the Justice Department’s national security division and U.S. attorney’s office for the District — warned in recent weeks that Concord’s requests could jeopardize the secrecy of a matter before a federal grand jury.

Earlier, prosecutors argued Concord’s moves also could reveal government investigative techniques and identify cooperating individuals and companies, as well as personal information of U.S. identity-theft victims whose data was used in the plot.

Friedrich, who said last year she would reconsider the question of sharing evidence with Prigozhin when the case was further along, scheduled a hearing for March 7 to do so.