Judge Juan M. Merchan on Monday afternoon briefly closed the courtroom where Donald Trump's criminal trial is being held, forcing reporters into the hallway after he admonished witness Robert Costello for his behavior.

Costello aggravated Merchan repeatedly in his testimony by making comments under his breath and continuing to speak after objections were sustained - a signal to witnesses to stop talking.

At one point, frustrated as he was again cut off by a sustained objection, Costello remarked, "Jeez."

"I'm sorry? I'm sorry?" a peeved Merchan asked.

"Strike it, I'm -." Costello replied, cutting himself off.

At another point, he called the whole exercise, "ridiculous."

After excusing the jury, Merchan told the witness: "Mr. Costello, I want to discuss proper decorum in my courtroom. When there's a witness on the stand, if you don't like my ruling, you don't say 'jeez'... You don't give me side eye and you don't roll your eyes."

"Are you staring me down right now? Clear the courtroom, right now. Clear the courtroom," the judge said.

For several minutes, there were no reporters in the courtroom or video access to the proceedings in the overflow room.

Jurors and reporters returned a short time later.

Defense witness Robert Costello, who for a time was Michael Cohen's attorney, introduced details of his first meeting with Cohen, saying they first met at the Regency Hotel in Manhattan on April 17, 2018, with attorney Jeffrey Citron.

Cohen "was absolutely manic" during the first meeting, Costello said. The FBI had just raided his home and office.

"I really want you to explain what my options are. What's my escape route?" Costello said Cohen told him.

Cohen said, "My life is shattered, my family's life is shattered," Costello testified.

Costello said he told Cohen, "This entire legal problem he was facing would be resolved by the end of the week if he had truthful information about Donald Trump and cooperated with the Southern District of New York."

Costello said that Cohen on multiple occasions said, "I swear to god Bob, I don't have anything on Donald Trump."

"Did the topic of Stormy Daniels come up?" defense attorney Emil Bove asked Costello.

Costello said it did, with Cohen telling him, "I don't understand why they're trying to put me in jail for some f------ NDAs."

Costello testified that in their initial meeting on April 17, 2018, Cohen said Trump did not know about the payment to Stormy Daniels.

"Michael Cohen said numerous times that President Trump knew nothing about those payments, that he did this on his own, and he said that numerous times," Costello testified.

"Jeez," Costello muttered when Judge Merchan sustained an objection following another question.

The judge had earlier instructed Costello to wait until an objection was resolved before answering the question.

Robert Costello, a former federal prosecutor in New York, is relevant to Donald Trump's hush money case due to his role as a Michael Cohen antagonist and critic in the years since their professional relationship splintered.

Costello had offered to represent Cohen soon after the lawyer's hotel room, office and home were raided by the FBI in 2018 and as he faced a decision about whether to remain defiant in the face of a criminal investigation or to cooperate with investigators in hopes of securing more lenient treatment.

During Cohen's testimony last week, prosecutors presented correspondence showing that Costello boasted about his closeness at the time with Trump ally Rudy Giuliani - a relationship he suggested could be beneficial to Cohen - and reassured him that he was "loved" inside the White House. In presenting those messages to the jury, prosecutors hoped to prove that Costello's outreach was designed to keep Cohen in the Trump fold and to discourage him from flipping on Trump.

But Cohen ultimately did exactly that, pleading guilty to federal crimes and implicating Trump. Costello in the years since has repeatedly maligned Cohen's credibility and was even a witness before last year's grand jury that indicted Trump, offering testimony designed to undermine his account.

Attorney Robert Costello was called to the witness stand in Donald Trump's hush money trial Monday afternoon.

Before he took the stand, Judge Juan M. Merchan ruled that he would allow the defense to question him about two allegedly inconsistent statements in Michael Cohen's testimony and to "offer some rebuttal" to his testimony.

But, Merchan said, he won't allow the questioning to become a "trial within a trial" as to whether there was a pressure campaign and how it affected Cohen.

The judge said he would give Trump lawyer Emil Bove "some latitude to explore the pressure campaign so you can explore some inconsistencies."