Claremont, New Hampshire – Former president Donald Trump faced furious backlash Monday over his Veterans Day weekend remarks branding his political opponents "vermin," as leading scholars and President Joe Biden accused him of parroting Hitler and Mussolini.

In a social media post to mark the holiday on Saturday, Trump pledged to "root out the Communists, Marxists, Fascists, and Radical Left Thugs that live like vermin within the confines of our Country, lie, steal, and cheat on Elections, and will do anything possible, whether legally or illegally, to destroy America, and the American Dream."

The tycoon – who leads polling in the race for the 2024 Republican presidential nomination – later repeated the remarks at a speech in New Hampshire that night.

"On a weekend when most Americans were honoring our nation's heroes, Donald Trump parroted the autocratic language of Adolf Hitler and Benito Mussolini – two dictators many US veterans gave their lives fighting – in order to defeat exactly the kind of un-American ideas Trump now champions," the Biden campaign said.

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The White House added separately that Trump's remark would be "horrifyingly recognizable to American veterans who put on their country's uniform in the 1940s."

The Trump campaign slammed "snowflakes" making the historical comparison and warned in a statement that "their sad, miserable existence will be crushed when President Trump returns to the White House."

Scholars including presidential historian Jon Meacham, New York University academic Ruth Ben-Ghiat, and Harvard constitutional law expert Laurence Tribe noted that Nazis had used the term "vermin" to characterize Jews as subhuman.

"To call your opponent vermin, to dehumanize them, is to not only open the door, but to walk through the door, toward the most ghastly kinds of crimes," said Meacham, a close ally of Biden.

Former Republican congressman and cable news host Joe Scarborough, who was discussing the remarks with Meacham on left-leaning MSNBC, said Trump should probably "pay some royalties to Mussolini's family trust."

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Trump regularly praises the leaders of regimes seen as authoritarian and adversarial to US interests, including Chinese President Xi Jinping, Russia's Vladimir Putin, and North Korean dictator Kim Jong Un.

But his use of what Tribe called "straight-up Nazi talk" is being seen as an escalation of his dark language. Similarly, Hillary Clinton likened him to Adolf Hitler in an interview last week.

"His danger to everyone's freedom and to each person's very survival is increasingly plain," Tribe said. "Please believe your eyes and ears. Trump is exactly what he appears to be!" the scholar posted on X.