Anti-Trump protesters gather in several US cities

Thousands of protesters have gathered in Washington DC and across the United States, part of about 1200 demonstrations that were expected to form the largest single day of protest against US President Donald Trump and his billionaire ally Elon Musk since they launched a rapid-fire effort to overhaul government.

People streamed onto the expanse of grass surrounding the Washington Monument under gloomy skies and light rain.

Organisers told Reuters that more than 20,000 people were expected to attend a rally at the National Mall.

About 150 activist groups had signed up to participate, according to the event's website.

Protests were planned in all 50 US states plus Canada and Mexico.

Terry Klein, a retired biomedical scientist from Princeton, New Jersey, was among those who gathered by the stage beneath the Washington Monument.

She said she drove down to attend the rally to protest Trump's policies on "everything from immigration to the DOGE stuff to the tariffs this week, to education. I mean, our whole country is under attack, all of our institutions, all the things that make America what it is".

The crowd around the memorial continued to build throughout the day.

Some carried Ukrainian flags and others wore Palestinian keffiyeh scarves and carried "Free Palestine" signs while Democrats from the US House of Representatives criticised Trump's policies on stage.

Wayne Hoffman, 73, a retired money manager from West Cape May, New Jersey, said he was concerned about Trump's economic policies including his widespread use of tariffs.

"It's going to cost the farmers in the red states. It's going to cost people their jobs - certainly their 401Ks. People have lost tens of thousands of dollars," Hoffman said.

Kyle, a 20-year-old intern from Ohio, was a lone Trump supporter, sporting a "Make America Great Again" hat and walking the fringe of the Washington DC rally while engaging protesters in debate.

"Most people aren't too hostile. A few people cuss," said Kyle, who declined to give his last name.

Trump, who shook financial markets and upset countries around the world with a raft of trade tariffs this week, spent the day in Florida, playing a round of golf at his club in Jupiter before returning to his Mar-a-Lago compound in the afternoon.

About 6km from Mar-a-Lago in West Palm Beach, more than 400 demonstrators gathered on a sunny day in protest.

Drivers honked their horns in support of the pastel-and khaki-clad demonstrators as they passed by.

"Markets tank, Trump golfs," read one sign.

With Trump's blessing, Musk's Department of Government Efficiency team has scythed through the US government, eliminating more than 200,000 jobs from the 2.3 million federal workforce.

At times, the effort has been haphazard and forced the recall of needed specialists.

On Friday, the Internal Revenue Service began laying off more than 20,000 workers, as much as 25 per cent of its ranks.

Several hundred people gathered outside the headquarters of the Social Security Administration, a top DOGE target, near Baltimore to protest against cuts to the agency which delivers benefits to the elderly and disabled.

Linda Falcao, who turns 65 in two months, told the crowd she had been paying into the Social Security fund since the age of 16.

"I'm terrified, I'm angry, I'm pissed, I'm bewildered this could happen to the United States," she said.

"I do love America and I'm heartbroken. I need my money. I want my money. I want my benefits!".

The crowd chanted, "It's our money!"

White House assistant press secretary Liz Huston disputed the protesters' charge that Trump aimed to cut Social Security and Medicaid.

"President Trump's position is clear: he will always protect Social Security, Medicare and Medicaid for eligible beneficiaries. Meanwhile, the Democrats' stance is giving Social Security, Medicaid, and Medicare benefits to illegal aliens, which will bankrupt these programs and crush American seniors," Huston said in an email.

Hours before the protests were due to kick off in the United States, hundreds of anti-Trump demonstrators living in Europe gathered in Berlin, Frankfurt, Paris and London to voice opposition to Trump's sweeping makeover of US foreign and domestic policies.