New York City police have thrown up metal barriers around Trump Tower and blocked roads near Manhattan Criminal Courthouse as they brace for potential protests ahead of Donald Trump’s expected to surrender to prosecutors on Tuesday.

The former president is due to be arraigned at the courthouse Tuesday afternoon, after his indictment in a grand jury probe over hush money paid to a porn star. He is the first former US. president to face criminal charges.

Trump describes the probe as a political witch hunt, and top supporters, including Republican lawmaker Marjorie Taylor Greene, say they will go to New York on Tuesday to protest. The downtown courthouse, home to criminal and supreme courts, will shut down some courtrooms ahead of Trump’s expected appearance, a court official said.

The New York Police Department (NYPD) said there were no credible threats to the city.

Some social media users have called for Manhattan District Attorney Alvin Bragg and the jury that indicted Trump to be executed, according to Site Intelligence Group, which monitors online extremism.

After Trump falsely claimed he won the last election, his supporters stormed the US. Capitol building on Jan. 6, 2021, sparking a deadly riot.

However, many Trump supporters online have expressed wariness about public demonstrations, even after Trump called for them, concerned they could be arrested.

“(The) department remains ready to respond as needed and will ensure everyone is able to peacefully exercise their rights,” the NYPD said in a statement.

Trump is expected to fly to New York on Monday from Florida and spend the night at Trump Tower, before arriving early Tuesday morning at the courthouse, a Trump adviser said.

While the spectacle of the former president facing criminal charges was certain to draw massive media attention, it is not yet clear if his appearance would draw a large number of protesters. While Trump is a native New Yorker, he didn’t get many votes in his hometown - 23% of the city voted for him in 2020 and 18% in 2016.

The New York Young Republican Club says it is planning a protest at a park across the street from the courthouse, a demonstration that Greene, one of Trump’s staunchest supporters in Congress, says she will attend.

“Protesting is a constitutional right,” Greene said on Twitter, adding that she would “protest this unprecedented abuse of our justice system and election interference.” She said she rejects anyone who incites or commits violence. Before voting to indict Trump, the grand jury heard evidence about a $130,000 payment to adult film actress Stormy Daniels in the waning days of the 2016 presidential campaign.

Daniels, whose real name is Stephanie Clifford, has said she was paid to keep silent about a sexual encounter she had with Trump in 2006. Trump denies the sexual encounter.

A court official told Reuters that courtrooms on higher floors of the courthouse will be closed at 1 p.m., shortly before Trump’s expected 2:15 p.m. (1815 GMT) arraignment.

The official also said many court cases will be adjourned at a building across the street from the courthouse.