• Former President Donald Trump took to social media and said he expects to be arrested Tuesday.
• A grand jury has been hearing testimony related to the 2016 payoff to Stormy Daniels, but no public announcements have been made about when or if Trump will be indicted.
• Trump cited leaks from the "corrupt" Manhattan district attorney's office and urged his supporters to protest on his behalf.

Former President Donald Trump said in a social media post Saturday that he expects to be arrested on Tuesday as a New York grand jury investigates his connection with a hush-money payment to a porn star.

Trump said he learned about his supposedly imminent arrest through leaks from the "corrupt" Manhattan District Attorney's Office. He urged his supporters to protest on his behalf — a call that is reminiscent of the time the former president encouraged thousands to flock to Washington, D.C., during the insurrection on Jan. 6, 2021.

"THE FAR & AWAY LEADING REPUBLICAN CANDIDATE & FORMER PRESIDENT OF THE UNITED STATES OF AMERICA, WILL BE ARRESTED ON TUESDAY OF NEXT WEEK," Trump wrote on his social media site Truth Social early Saturday morning. "PROTEST, TAKE OUR NATION BACK!"

In another emphatic post on Saturday afternoon, Trump tried to galvanize his base further.

"WE JUST CAN'T ALLOW THIS ANYMORE," he wrote. "THEY'RE KILLING OUR NATION AS WE SIT BACK & WATCH. WE MUST SAVE AMERICA!PROTEST, PROTEST, PROTEST!!!"

A grand jury has been hearing testimony related to the 2016 payoff to Stormy Daniels at the state Criminal Court in lower Manhattan, but no public announcements have been made about when or if Trump will be indicted. Law enforcement agencies across New York have been making security arrangements in the case that the former president is criminally charged.

Trump's lawyer Joseph Tacopina was not informed about the possibility of Trump being arrested on Tuesday.

"No one tells us anything, which is very frustrating," Tacopina told CNBC. "President Trump is basing his response on press reports, and the fact that this is a political prosecution and the DA leaks things to the press instead of communicating to the lawyers as they should."

If he is indicted, Trump, a 2024 Republican presidential candidate, would become the first former president ever to face criminal charges.

U.S. House Speaker Kevin McCarthy shared a tweet in support of Trump Saturday, calling the District Attorney a "radical" in pursuit of "political vengeance" against the former president.

"I'm directing relevant committees to immediately investigate if federal funds are being used to subvert our democracy by interfering in elections with politically motivated prosecutions," he wrote in the tweet.

The Manhattan District Attorney's office declined to comment.

—CNBC's Dan Mangan contributed to this report.