Protesters spanning all age groups, many with children and pets in tow, took to the streets en masse for"No Kings" rallies across the United States on Saturday (Oct 18), denouncing what they view as authoritarian tendencies and unbridled corruption of US President Donald Trump.

Organisers expected millions of people to turn out by day's end at more than 2,600 planned rallies in major cities, small towns and suburbs, challenging a Trump-led agenda that has reshaped the government and upended democratic norms with unprecedented speed since he took office in January.

By all accounts, the demonstrations were largely festive, many featuring inflatable characters and marchers dressed in red, white and blue. The demographically mixed crowds included many parents pushing youngsters in strollers alongside elderly participants.

Little, if any, lawlessness was reported.

DISILLUSIONED WITH TRUMP

"There is nothing more American than saying, 'We don't have kings’ and exercising our right to peacefully protest,” said Leah Greenberg, co-founder of Indivisible, a progressive organisation that led planning of Saturday's events.

Demonstrators filled Times Square in New York City, where police said they made"zero protest-related arrests" even as more than 100,000 people rallied peacefully across all five boroughs.

Events in Boston, Philadelphia, Atlanta, Denver, Chicago and Seattle also drew crowds that each appeared to encompass thousands, if not tens of thousands, of people.

On the West Coast, more than a dozen rallies occurred around the Los Angeles area, including the primary site downtown.

In Seattle, demonstrators filled a parade route that stretched for more than a kilometre from downtown through the Seattle Center plaza around the city's landmark Space Needle. More than 25,000 protested peacefully in San Diego, police said.

The protests reflected growing unease among many Americans, mainly on the ideological left, with developments such as the criminal prosecution of Trump's perceived political enemies, his militarised immigration crackdown and the sending of National Guard troops into US cities - a move Trump has said was aimed at fighting crime and protecting immigration agents.

As his administration has tried to rapidly implement its policies, Trump has installed inexperienced loyalists throughout the ranks of his administration and sought to apply pressure on the news media, law firms and higher education.

The rallies were boisterous but orderly, with police largely keeping a low profile.

In Washington, demonstrators filled the street as they marched toward the US Capitol, chanting and carrying signs, US flags and balloons. Many people - and their dogs - wore costumes in a relaxed, carnival-like atmosphere.

Protester Aliston Elliot, wearing a Statue of Liberty headpiece and holding a"No Wannabe Dictators" sign, said:"We want to show our support for democracy and for fighting (for) what is right. I'm against the overreach of power."

In downtown Houston, US Marine Corps veteran Daniel Aboyte Gamez, 30, joined a crowd that officials said numbered about 5,000 at city hall on Saturday afternoon.

"I don't understand what's going on in this nation right now," said Gamez, who served in Iraq, Afghanistan and Syria.

"FORMER REPUBLICAN"

Kevin Brice, 70, a military veteran among thousands of protesters streaming into the riverfront area of Portland, Oregon, wore a black sweatshirt emblazoned with the slogan"No Kings since 1776" - referring to the year of the Declaration of Independence.

"Everything that I thought that I stood for while I was serving in the military seems to be at risk," Brice said."So even though I’m a lifelong Republican, I don’t support the direction the party is going."

Steve Klopp, 74, a Houston-based oil industry retiree, expressed similar sentiments as he wore a shirt with the words"Former Republican" on it.

"I've been a Republican forever," Klopp said."My family's been Republican forever and ever. And the idea that one individual could have turned me away from the Republican Party is insane."

Kelly Kinsella, 38, standing among several thousand people gathered outside the Colorado statehouse in Denver, was dressed as the Statue of Liberty, with bloody tears dripping down her face, and carried a"No Kings" sign.

“Everyone comes to work stressed, and it's because of the current conditions," said Kinsella, who said she was motivated to turn out largely because of renewed inflation that she blamed on Trump's tariff policies.

TRUMP SAYS HE IS NOT A KING

Trump has said little about Saturday’s protests. But in an interview with Fox Business aired on Friday, he said:"They're referring to me as a king - I'm not a king.”

More than 300 grassroots groups helped organise Saturday's marches, Greenberg said. The American Civil Liberties Union said it provided legal guidance and"de-escalation" training to tens of thousands of people to act as marshals at the various marches.

While the Democratic Party has coped with internal divisions over the best way to oppose Trump, party establishment figures such as Senate Minority Leader Chuck Schumer and progressive firebrands like US Representative Alexandria Ocasio-Cortez both voiced their support for the"No Kings" movement.

Saturday's protests were aimed at building on grassroots momentum gained by organisers of some 2,000-plus"No Kings" protests that were staged on Jun 14, coinciding with Trump's 79th birthday and a rare military parade in Washington.

REPUBLICANS CLAIM PROTESTS ARE ANTI-AMERICAN

House of Representatives Speaker Mike Johnson, a Republican, on Friday echoed a common refrain among his party, labeling the"No Kings" protests "the hate America rally".

Other Republicans have accused organisers of the rallies of stoking an atmosphere that might spur more political violence, especially in the wake of the September assassination of right-wing activist and Trump ally Charlie Kirk.

Vice President JD Vance, speaking on Saturday to a gathering of Marines at Camp Pendleton in Southern California, made no mention of the protests. But he criticised Democrats over the government shutdown that began early this month in a partisan standoff over federal appropriations.

Dana Fisher, a professor at American University in Washington and author of several books on American activism, forecast that Saturday could see the largest protest turnout in modern US history.

She expected that over 3 million people would take part based on registrations and participation in the June events.

Overall turnout for the Jun 14"No Kings" rallies was estimated at 4 million to 6 million, according to a crowd-sourcing analysis published by the prominent data journalist G Elliott Morris on his Strength in Numbers blog site.

Fisher said the protests were"not going to change Trump's policies", but could"embolden elected officials at all levels who are in opposition to Trump".