Washington DC - Huge crowds took to the streets Saturday in all 50 states to vent their anger over President Donald Trump's hardline policies at sprawling "No Kings" protests.

From New York and Washington to smaller cities in Michigan and Trump's second home in Florida, demonstrations in the eastern half of the US revved up ahead of similar events due out west.

More than 2,700 protests are planned coast to coast, and organizers say they are expecting millions to attend.

"This is what democracy looks like!" chanted thousands at a protest in Washington near the National Mall, home to the city's iconic landmarks.

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"Hey hey, ho ho, Donald Trump has got to go!" said protesters, many of them carrying American flags.

Demonstrators are up in arms over the authoritarian tactics employed by the Republican billionaire since he returned to the White House in January, including attacks on the media, the prosecution of political opponents, and an aggressive immigration crackdown.

A government shutdown is now in its third week, with the Trump administration firing thousands of federal workers and lawmakers showing little sign they are ready to break the impasse.

Thousands flooded New York's Times Square, Boston Common, and Chicago's Grant Park.

"I never thought I would live to see the death of my country as a democracy," 69-year-old retiree Colleen Hoffman told AFP as she marched down Broadway.

"We are in a crisis – the cruelty of this regime, the authoritarianism. I just feel like I cannot sit home and do nothing."

In New York's Queens borough, demonstrators carried colorful signs that read "Queens Say No Kings," and "We protest because we love America and want it back!" while some chanted, "We love our country, we can't stand Trump!"

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In Los Angeles, organizers plan to float a giant balloon of Trump in a diaper. They said they expect 100,000 people to attend.

So far, Trump's response to Saturday's events has been muted.

"They're saying they're referring to me as a king. I'm not a king," he told Fox News show Sunday Morning Futures.

But his top surrogates were in more fighting form, with House Speaker Mike Johnson calling the day of protest the "Hate America rally."

Republican lawmaker Tom Emmer also used the "Hate America" phrase and referred to participants as the "terrorist wing" of the Democratic Party.

Beyond the US, the "No Kings" movement is even organizing events in Canada, and small protests took place Saturday in Malaga, Spain, and Malmo, Sweden.

On Thursday, Deirdre Schifeling, chief political and advocacy officer for the American Civil Liberties Union, said protesters wanted to convey that "we are a country of equals."

"We are a country of laws that apply to everyone, of due process and of democracy. We will not be silenced," she told reporters.

Leah Greenberg, co-founder of the Indivisible Project, slammed the Trump administration's efforts to send the National Guard into US cities and crack down on undocumented migrants.

Trump has ordered National Guard troops into Los Angeles, Washington, and Memphis. Planned deployments to Chicago and Portland, Oregon, have so far been blocked in the courts.

"It is the classic authoritarian playbook: threaten, smear and lie, scare people into submission," Greenberg said.

Top Democratic Senator Chuck Schumer encouraged demonstrators to let their voices be heard.

"I say to my fellow Americans this No Kings Day: Do not let Donald Trump and Republicans intimidate you into silence. That's what they want to do. They're afraid of the truth," he wrote Saturday on X.

"Speak out, use your voice, and exercise your right to free speech."