In a dramatic day at a New York courthouse during former US President Donald Trump's hush money trial, the judge cleared reporters from the courtroom after a witness expressed disdain on Monday.

Judge Juan M. Merchan told Robert Costello, a longtime Trump ally, that his conduct was "contemptuous right now." 

"If you try to stare me down one more time, I will remove you from the stand," Merchan said.

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, Costello could be hear saying "jeez" and "ridiculous" from the witness stand.

Judge Merchan subsequently ordered reporters out of the courtroom before allowing them back in a few minutes later. 

Prosecution rests case against Trump in hush money trial

Costello has previously worked for Michael Cohen, Trump's estranged former fixer and lawyer. Cohen is the prosecution's key witness in the hush money trial.

Prosecutors have used Cohen's testimony to convince jurors that Trump falsified business documents to cover up a payment to adult film actress Stormy Daniels before the 2016 elections, which they say impacted the outcome.

Cohen has accused his former boss of directing the hush money payment to Daniels that's at the center of the criminal case.

Trump calls judge a 'tyrant'

Trump spoke to reporters for about 15 minutes after leaving the court for the day, calling the judge a "tyrant" and mentioning the judge's chastising of Costello.

“I’ve never seen anything like that,” Trump said.

The prosecution rested in its case on Monday. Trump's side began its defense Monday afternoon local time and closing arguments are expected next week.

Trump's team is asking Judge Merchan for an order dismissing the case immediately, with lawyer Todd Blanche arguing that prosecutors have failed to prove their case and that there's no evidence of falsified business records.

rm/jsi (Reuters, AP, AFP)