Robert De Niro, former police officers slam Trump outside New York hush money trial

The Biden campaign on Tuesday dispatched actor Robert De Niro and two former police officers who defended the U.S. Capitol on Jan. 6, 2021 -- Harry Dunn and Michael Fanone -- to convey the threat they argued former President Donald Trump poses to the country.

Speaking to reporters near the Manhattan courthouse where Trump's criminal hush money trial is taking place, De Niro said Trump "wants to sow total chaos."

De Niro, a New Yorker, called Trump a "clown" whose presidency could be dangerous for Americans. He said New Yorkers once tolerated Trump, but now recognize him as a threat.

"I love this city. I don't want to destroy it. Donald Trump wants to destroy not only the city, but the country, and eventually he can destroy the world," De Niro said.

At a press conference following the Biden campaign's, Trump campaign senior adviser Jason Miller shot back, saying the best the Biden campaign could do in attacking Trump was to "roll out a washed-up actor."

De Niro said that if "Trump returns to the White House, you can kiss these freedoms goodbye that we all take for granted."

De Niro recently voiced an anti-Trump ad for the Biden campaign. He said he agreed to participate in the ad "because it shows the violence of Trump and reminds us that he'll use violence against anyone who stands in the way of his megalomania and greed."

Dunn and Fanone both defended the Capitol on Jan. 6, and have been some of the most outspoken members of law enforcement to condemn the attacks. They were both witnesses during the congressional investigation of the Jan. 6 attacks.

Dunn -- who failed in his bid for Congress earlier this month, losing the Democratic primary to represent Maryland's 3rd Congressional District -- called Trump the "greatest threat to our democracy."

"Donald Trump is the greatest threat to our democracy and the safety of communities across the country today," Dunn said. "We've been called traitors, just today. We were all called traitors on Jan. 6 for doing our job," Dunn said.

Fanone, who was a D.C. police officer, was assaulted by rioters on Jan. 6 and suffered a heart attack from the assault.

"I came here today to remind Americans of what Donald Trump is capable of and the violence that he unleashed on all of Americans on Jan. 6, 2021," Fanone said.

Tuesday's appearance marked the first time the Biden campaign has engaged in any activity outside the courthouse in lower Manhattan. The Trump campaign has had surrogates in the Collect Pond Park near the courthouse every day for the past three weeks speaking on behalf of the former president.

During the Trump campaign's rebuttal, Miller criticized the Biden supporters' appearance.

"The Biden folks have finally done it. After months of saying politics had nothing to do with this trial, they showed up and made a campaign event out of a trial day for President Trump," Miller said.

-ABC News' Kelsey Walsh contributed to this report.