Former President Donald Trump has been charged with around two dozen counts, including felonies, sources familiar with the sealed indictment told ABC News.

The exact charges remain unknown since the indictment will not be unsealed until Trump appears in court on Tuesday.

The Manhattan district attorney’s office declined to comment.

The Senate sergeant at arms is warning of potential demonstration activity related to the indictment of former President Donald Trump.

"While law enforcement is not tracking any specific, credible threats against the Capitol or state offices, there is potential for demonstration activity," an email obtained by ABC News said.

Capitol Police "is working with law enforcement partners, so you may observe a greater law enforcement presence on Capitol Hill," the email said, adding that there could be "nationwide impacts to Senate state offices."

The Capitol Police declined to comment and the sergeant at arms didn't immediately respond to ABC News' request for comment.

-ABC News' Luke Barr

Former President Donald Trump's daughter, Ivanka Trump, reacted to the indictment on Instagram Friday, writing, "I love my father, and I love my country. Today, I am pained for both."

She added, "I appreciate the voices across the political spectrum expressing support and concern."

Sources familiar with the matter told ABC News the Manhattan district attorney’s office is also investigating a $150,000 payment to Playboy model Karen McDougal, who, like Stormy Daniels, claimed to have had an affair with Donald Trump.

The former president has denied having an affair with either woman and has called the investigation a witch hunt.

McDougal was paid for the rights to her story in August 2016 by American Media, publisher of the National Enquirer, which did not publish it, a practice known as catch and kill.

Michael Cohen, Trump’s former lawyer and fixer, has said he recorded Trump discussing reimbursement to American Media for the payment to McDougal, but the payment was never made.

Trump has not responded to ABC News' request for comment but in a 2018 interview with Fox News, he claimed he wasn't aware of any payment made to AMI to facilitate the alleged hush agreement.

Donald Trump's former personal attorney and fixer Michael Cohen said the ex-president is likely "seething" over the indictment because he's "never been held accountable."

"The fact that he is being held accountable, something that he has no desire to ever be. He's never been held accountable," Cohen told ABC News' George Stephanopoulos in an interview Friday on "Good Morning America."

"This is a man who held up the Bible and said he's never apologized to God because he's never done anything wrong," he added. "He doesn't understand accountability. And right now, [Manhattan District Attorney] Alvin Bragg has finally put that into his lap."

Cohen, who is now estranged from Trump and is a key prosecution witness, said he decided years ago that his "loyalty can no longer be to a man who doesn't deserve it."

Cohen was sentenced to three years in prison in December 2018, after pleading guilty to violating federal campaign finance law in connection with hush-money payments and lying to Congress, among other crimes.

During Friday's interview on "GMA," Cohen said he followed Trump's "message" for more than a decade and "that is what got me in trouble."

When asked if he feels ready to be cross-examined, Cohen replied: "Absolutely."

"The documents will speak for themselves," he added, referring to the sealed indictment.

"So, not just your testimony?" Stephanopoulos responded.

"No," Cohen said. "And it's also corroborating testimony, but it's documents."