Former National Enquirer publisher David Pecker, back on the witness stand, pointed at Donald Trump and flashed a smile when he was asked to identify the defendant. Trump turned his chin up and grinned at his longtime friend.

"I met Mr. Trump at Mar-a-Lago," Pecker said. "I've had a great relationship with Mr. Trump over the years."

That relationship started in 1989 when Pecker wanted to start a magazine called Trump Style.

"He was very helpful in introducing me to other executives in New York. He would always advise me of parties or events that I would go to," Pecker said, adding that Trump was among the first to congratulate him upon acquiring the National Enquirer.

Pecker described how Trump became a "major celebrity" after launching The Apprentice and later Celebrity Apprentice, and how the National Enquirer was there to juice Trump's profile.

"He was always kind enough to send me the content showing the ratings and I was able to publish that," Pecker said of their "great mutual beneficially relationship.

Pecker said he considered Trump a friend from 2015 to 2017, calling him by the familiar "Donald," as he pursued the White House for the first time.

"After he announced his run for the presidency I saw Mr. Trump more frequently, maybe once a month," Pecker said. The two spoke "maybe once every couple of weeks."

Pecker recalled meeting Trump in his office when his assistant brought a batch of invoices and checks to sign.

"As I recollect the entire package was stapled together," Pecker said.

"So you observed him reviewing an invoice and signing a check?" prosecutor Josh Steinglass asked. "That's correct," Pecker responded.

"I would describe him as very knowledgeable, very detail-oriented, almost as a micromanager," Pecker said.

When Steinglass asked how Trump was with money, Pecker responded, "He was very cautious and very frugal."

The U.S. Secret Service has held meetings and started planning for what to do if former President Trump were to be held in contempt and Judge Juan Merchan opted to send him to short-term confinement, officials familiar with the situation tell ABC News.

Prosecutors said at this point they are seeking a fine.

"We are not yet seeking an incarceratory penalty," assistant district attorney Chris Conroy said, "But the defendant seems to be angling for that."

Officials do not necessarily believe Merchan would put Trump in a holding cell in the courthouse but they are planning for contingencies, the officials said.

There have be no discussion about what to do if Trump is convicted and sentenced to prison, they said.

"Under federal law, the United States Secret Service must provide protection for current government leaders, former Presidents and First Ladies, visiting heads of state and other individuals designated by the President of the United States," the Secret Service said in an official statement. "For all settings around the world, we study locations and develop comprehensive and layered protective models that incorporate state of the art technology, protective intelligence and advanced security tactics to safeguard our protectees. Beyond that, we do not comment on specific protective operations."

-Josh Margolin and Luke Barr

The combative hearing on Trump's alleged violations of the judge's limited gag order ended with the judge saying he will not rule from bench on the district attorney's motion to hold Trump in contempt, so a ruling will come later.

Before concluding the hearing, Judge Merchan told Trump attorney Todd Blanche, "You're not offering me anything … to hang my hat on."

The trial will resume shortly with the return of former National Enquirer publisher David Pecker to the witness stand.

Judge Juan Merchan is visibly irritated with the lack of evidence presented by defense attorney Todd Blanche.

"You have presented nothing," Merchan said. "I have asked eight or nine times; show me the exact post he was responding to."

"You're losing all credibility with the court," Merchan said after Blanche suggested Trump has been careful to comply with the gag order.

Blanche attempted to represent that Trump did not intend to violate the gag order, but Merchan did not appear satisfied by the response.

"Are you testifying under oath that this is his position?" Merchan asked.

"Do you want me to put him on the stand?" Blanche asked, though Trump did not take the stand.

Merchan strongly reacted earlier when Blanche suggested there were two tiers of justice in the courtroom.

"There are two systems of justice. Mr. Weisselberg is in prison, and Mr. Cohen is a witness," Blanche said, in reference to the former Trump Organization CFO who was sentenced to jail time for perjury.

"There are two systems of justice in this courtroom -- is that what you are saying?" Merchan responded.

Exiting court after a lengthy day of proceedings, former President Trump complained about the scheduling conflicts created by his criminal trial, including conflicts with his presidential campaign, his plans to attend Supreme Court oral arguments, and potentially his son Barron's high school graduation.

"Now I can't go to my son's graduation," Trump said. "I can't go to the United States Supreme Court. I'm not in Georgia or Florida or North Carolina campaigning like I should be," Trump told reporters outside court.

Trump repeated his past complaints about the fairness of the trial, saying he has a "real problem" with Judge Merchan.

"It's a scam, it's a political witch hunt," Trump said. "We're not going to be given a fair trial."