Before today's first witness entered court, Trump attorney Chris Kise asked Judge Engoron to postpone today's proceedings after five members of the New York attorney general's team tested positive for COVID-19.

Describing the attorney general's conduct as "beyond irresponsible," Kise said that his team did not get adequate notice about the COVID exposures despite having close contact with positive individuals.

"Nothing else matters except for pursuing President Trump," Kise said. "We have the leading candidate for president of the United States in the courtroom today."

"The attorney general's office knew on Wednesday and didn't tell any of us," defense attorney Clifford Robert said. "We are truly in an outbreak."

Engoron declined to grant their requested delay.

In a statement, a spokesperson for New York Attorney General Letitia James said the state has complied with all CDC guidelines.

"Our office properly notified the court and defendants' counsel, and the court decided to proceed with trial today. If there were any concerns, defendants could wear masks today or at any point, but they have opted not to," the spokesperson said.

Trump called his former lawyer Michael Cohen a "proven liar" and "felon" as Trump entered the courtroom for his civil trial this morning.

"He's a felon, served a lot of time for lying, and we're just going to go in and see and I think you'll see that for yourself," Trump told reporters outside court.

Cohen pleaded guilty in 2018 to two separate criminal cases and eventually spent more than 13 months in prison -- but said that it was Trump who caused him to "follow a path of darkness."

-ABC News' Ricardo Montero contributed to this report.

Exiting his New York City apartment this morning, Michael Cohen told reporters he was "looking forward" to seeing Trump in court.

"It's been five years since we've been in the same room," Cohen said.

Cohen preemptively defended the credibility of his testimony and reiterated that he previously perjured himself "concert with and for the benefit of Donald J. Trump."

"My credibility should not be in question," Cohen said.

-ABC News' Eric Avram contributed to this report.

Donald Trump has arrived in court for the anticipated testimony of his former lawyer Michael Cohen.

New York Attorney General Letitia James is also attending the trial this morning.

James took her usual seat at the front of the courtroom's gallery, directly behind her team of lawyers at the counsel table.

The courtroom itself is nearly at capacity, with attendance matching the number of observers during the trial's opening statements.

Deutsche Bank managing director Dave Williams downplayed the possibility that Donald Trump could have defaulted on the net-worth covenants included in his loans.

While both parties agree that Trump never defaulted on his loans, New York Attorney General Letitia James alleges that had Trump accurately reported the value of his assets, he could have risked defaulting on a loan covenant that required he maintain a net worth of $2.5 billion.

Defense attorney Jesus Suarez pushed back on that allegation by asking Williams about the severity of a covenant default -- i.e., breaching the terms of the loan -- compared to a payment default triggered by a missed payment.

"Generally speaking, a payment default is a more material default than a covenant default," Williams said. "It speaks definitively to the repayment of the loan."

Williams described a loan covenant as a "guardrail," and suggested that breaching the covenant would have brought Trump back to the negotiating table to adjust the loan terms.

Williams also reiterated that he was not aware of any loan or covenant defaults by Trump.

James is expected to request a fine of nearly $400 million for Trump's allegedly ill-gotten gains, including over $140 million based on the potential interest she says was lost by Deutsche Bank. By proving that the loan agreements were lawful, Trump's lawyers could significantly lower the fine Trump faces.