President Trump is facing multiple charges of falsifying business records, including at least one felony offense, in the indictment handed down by a Manhattan grand jury, two people familiar with the matter told the Associated Press on Friday. A lawyer for Mr. Trump vowed to fight the charges “very aggressively.”

He will be formally arrested and arraigned Tuesday in his hush money case, setting the scene for the historic moment when a former president is forced to stand before a judge to hear the criminal charges against him.

The indictment is still sealed, as is standard in New York before arraignment, and the specific charges were not immediately known, but details were confirmed by people who spoke on condition of anonymity to discuss information that isn’t yet public.

The streets outside the courthouse where the arraignment will unfold were calm Friday compared with earlier in the week. There were no large-scale demonstrations for or against Mr. Trump, though tourists stopped to take selfies and throngs of reporters and police officers remained assembled.

When Mr. Trump turns himself in, he’ll be booked mostly like anyone else facing charges, mug shot, fingerprinting, and all. He isn’t expected to be put in handcuffs; he’ll have Secret Service protection and will almost certainly be released the same day.

In the meantime, Mr. Trump’s legal team prepared his defense while the prosecutor’s office defended the grand jury investigation that propelled the matter toward trial. Congressional Republicans, as well as Mr. Trump himself, contend the whole matter is politically motivated.

“We urge you to refrain from these inflammatory accusations, withdraw your demand for information, and let the criminal justice process proceed without unlawful political interference,” the general counsel in the office of the Manhattan district attorney Alvin Bragg wrote in a letter sent Friday to the chairmen of three Republican House committees.

The case is plunging the U.S. into uncharted legal waters, with Mr. Trump the first former president ever to face an indictment. And the political implications could be titanic ahead of next year’s presidential election. 

Mr. Trump is in the midst of running for president a third time and has said the case against him could hurt that effort — though his campaign is already furiously raising money by citing it.

The Trump campaign said it raised $4-plus million in the first 24 hours after news of the indictment broke.

Top Republicans also have begun closing ranks around him. Speaker McCarthy has promised to use congressional oversight to probe Mr. Bragg. 

Representatives James Comer, Jim Jordan and Bryan Steil, the committee chairmen whom Mr. Bragg addressed in his letter, have asked the district attorney’s office for grand jury testimony, documents and copies of any communications with the Justice Department.

Mr. Trump’s indictment came after a grand jury probe into hush money paid during the 2016 presidential campaign to squelch allegations of an extramarital sexual encounter. 

The investigation dug into six-figure payments made to porn actress Stormy Daniels and former Playboy model Karen McDougal. Both claim to have had sexual encounters with the married Mr. Trump years before he got into politics. He denies having sexual liaisons with either woman.

Mr. Trump also has denied any wrongdoing involving payments and has denounced the investigation as a “scam,” a “persecution,” an injustice. He shouts in all capital letters on his social media platform that the Democrats have “LIED, CHEATED” and more to damage his 2024 presidential run.

Trump lawyer Joseph Tacopina said during TV interviews Friday he would “very aggressively” challenge the legal validity of the Manhattan grand jury indictment. Mr. Trump himself, on his social media platform, trained his ire on a new target, complaining that the judge expected to handle the case, Juan Manuel Merchan, “HATES ME.”

The former president is expected to fly to New York on Monday and stay at Trump Tower overnight ahead of his planned arraignment Tuesday, according to two people familiar with his plans who spoke on condition of anonymity to discuss Mr. Trump’s travel.

Trump will be arraigned in the same Manhattan courtroom where his company was tried and convicted of tax fraud in December and where disgraced movie mogul Harvey Weinstein’s rape trial took place. On Friday, officials from the Secret Service and the NYPD toured the courthouse and met about security plans.

Court officers ultimately closed and secured access to the 15th floor, where Judge Merchan was continuing to preside over unrelated matters, until Mr. Trump’s arraignment.

Lawyers involved in the cases and some employees were permitted to stay, but media were chased away by officers, who were standing sentry in front of a bike-rack barricade set up in the hallway. Officers yelled at reporters who ventured up, “This floor is closed,” and ordered them to get back in the elevator and leave.

“Officers have been cautioned to remain vigilant and maintain situational awareness, both inside courthouses and while on perimeter patrols, as evidenced by the incident on Tuesday afternoon outside of Manhattan Supreme Court,” the court said in a statement.

Since no former president had ever been charged with a crime, there’s no rulebook for booking the defendant. He will be fingerprinted and have a mug shot taken, and investigators will complete arrest paperwork and check to see if he has any outstanding criminal charges or warrants, according to a person familiar who requested anonymity to discuss sensitive security operations.

All of that activity takes place away from the public. New York law discourages the release of mug shots in most cases. Less clear is whether Mr. Trump would seek to have the picture released himself, for political or other reasons.

Once the booking is complete, the former president would appear before a judge for an afternoon arraignment.

Even for defendants who turn themselves in, answering criminal charges in New York generally entails at least several hours of detention while being fingerprinted, photographed, and going through other procedures.

The New York indictment came as Trump contends with other investigations. In Atlanta, prosecutors are considering whether he committed any crimes when trying to get Georgia officials to overturn his narrow 2020 election loss there to President Biden.

At the federal level, a Justice Department-appointed special counsel also is investigating Mr. Trump’s efforts to challenge the national election results. 

Additionally, the special counsel is examining how and why Trump held onto a cache of top secret government documents at his Florida club and residence, Mar-a-Lago, and whether the ex-president or his representatives tried to obstruct the probe into those documents.