Donald Trump stormed out of his $250 million New York fraud trial Wednesday, shortly after a judge fined him for violating his gag order and then rejected a defense attorney's bid for a verdict in Trump's favor.

The visibly angry former president's sudden departure elicited gasps from the courtroom and sent his own Secret Service agents chasing after him, NBC News reported.

Trump left while Michael Cohen, his former personal lawyer who is a star witness against him in the case, was still on the stand.

Cohen, under cross-examination, said he did not recall if Trump had asked him to inflate the values of his assets on financial records at the heart of the civil case.

Cliff Robert, an attorney for the Trump family, then asked Manhattan Supreme Court Judge Arthur Engoron for a directed verdict based on Cohen's answer. The judge denied the request — and Trump immediately got up and left.

It was only the latest clash between the judge and the defendants that afternoon.

Shortly beforehand, Engoron fined Trump $10,000 for once again violating a gag order barring him from targeting the judge's staff.

Engoron had summoned Trump to the witness stand to explain comments he made outside the courtroom earlier in the day, when he complained about a "very partisan judge with a person who's very partisan sitting alongside him, perhaps even much more partisan than he is."

The judge took that as a reference to his law clerk, Allison Greenfield, who sits next to Engoron in court.

Trump had previously been barred from making public statements about Engoron's staff, after he sent a social media post attacking Greenfield on the second day of the trial.

Under questioning from Engoron about his latest remarks, Trump said that he was referring to Cohen, who has been testifying throughout the trial day.

But Engoron said that answer was not credible, based on the language Trump used.

"Don't do it again or it will be worse," Engoron warned after issuing the fine.

Engoron's ruling is the second time Trump has been found in violation of his gag order in the civil fraud trial. Engoron fined Trump $5,000 last week, warning that future violations could carry much more severe sanctions, including imprisonment.

The fireworks came at the end of the second day of testimony from Cohen, who faced a barrage of attacks about his credibility as a witness.

Trump and his legal team had spent much of the previous trial day targeting Cohen's criminal history, attempting to paint him as a "serial liar" whose word could not be trusted.

Trump doubled down Wednesday during a mid-morning break, saying Cohen "went to jail for lying" and branding him "a totally discredited witness."

New York Attorney General Letitia James' civil case accuses Trump, his two adult sons, the Trump Organization and top executives of falsely inflating the values of Trump's real estate properties and other assets in order to get tax benefits and better loan terms.

James seeks around $250 million in damages, and she wants to bar Trump and his co-defendants from running another business in New York.

In his first day on the stand, Cohen had accused Trump of directing him and another Trump Organization executive to falsely inflate the values of his assets on financial statements.

Trump "would look at the total assets and say, 'I'm actually not worth $4.5 billion. I am really worth more like $6 billion,'" Cohen testified under oath.

But Trump's attorney Alina Habba grilled Cohen on cross-examination, highlighting his 2018 guilty plea on charges including lying to Congress. Habba asked him if he lied to the judge in that case during his plea hearing, and Cohen replied that he had.

On Wednesday, Habba picked up where she left off, needling Cohen on his admission of lying to the judge before accusing him of "cashing in" on his current antagonism toward Trump.

Cohen has implicated his former boss in some of the crimes that he himself pleaded guilty to, including making secret hush-money payments to women who said they had extramarital affairs with Trump, and lying about his business dealings with Russia. Trump has pleaded not guilty in a separate New York criminal case charging him with falsifying business records related to the hush-money payments.

Cohen, Trump's once-loyal aide, is now a star witness against him in James' trial. Cohen's 2019 testimony to Congress about Trump's allegedly fraudulent business practices is what led James to open her sweeping investigation.

Engoron, who will deliver verdicts in the no-jury trial, has already found Trump liable for fraud and ordered the cancellation of the defendants' New York business certificates. The trial, which is expected to stretch into late December, will resolve James' six remaining claims.

Cohen's 'animosity' toward Trump in focus

Habba, in an apparent attempt to establish a financial motive for the witness, contrasted Cohen's current loathing for Trump with his past statements overflowing with praise for his then-boss.

Cohen confirmed in court that he once had said he would "take a bullet" for Trump and had vowed to "never walk away" from him.

She then questioned whether Cohen sought a job in Trump's White House following his 2016 election victory. Cohen said he did not, adding that he received the job of personal attorney that he had asked for.

Habba quoted Cohen's words from his tell-all memoir "Disloyal," saying that "of course" he was "cashing in" on his relationship with Trump.

When she asked if Cohen had "significant animosity" toward Trump, Cohen replied, "Yes, I do."

Cohen also agreed that his career now involves publicly attacking Trump.

The bubbling tensions between the lawyers and the witness occasionally boiled over.

"I have answered every question that you want. Why are you screaming at me?" Cohen asked Habba at one point. 

Trump, who stared down Cohen in court on Tuesday, repeatedly attacked his former lawyer in between the proceedings. He called Cohen a "proven liar," a "felon" and a "disgrace" outside the courtroom.

He launched more attacks on social media, writing Tuesday evening that Cohen "was a complete and total disaster" in the trial.

"Lie after lie, and getting caught each time," claimed Trump.

Cohen declined CNBC's request for comment ahead of his testimony Wednesday, noting in an email that Engoron has directed him not to discuss the case while he is a witness.

An attorney for Cohen did not respond to a request for comment.

This is developing news. Please check back for updates.