Crowds of protesters gathered in cities across the US on Saturday to denounce President Trump, in the largest nationwide show of opposition since the president took office in January.

The "Hands Off" protest planners aimed to hold rallies in 1,200 locations, including in all 50 US states. Hundreds of thousands of people turned out in Boston, Chicago, Los Angeles, New York and Washington DC, among other cities.

Protesters cited grievances with Trump's agenda ranging from social to economic issues.

Coming days after Trump's announcement that the US would impose import tariffs on most countries around the world, gatherings were also held outside the US, including in London, Paris and Berlin.

In Boston, some protesters said they were motivated by immigration raids on US university students that have led to arrests and deportation proceedings.

Law student Katie Smith told BBC News that she was motivated by Turkish international student Rumeysa Ozturk, whose arrest near Boston-area Tufts University by masked US agents was caught on camera last month.

"You can stand up today or you can be taken later," she said, adding: "I'm not usually a protest girlie."

In London, protesters held signs reading, "WTAF America?", "Stop hurting people" and "He's an idiot".

They chanted "hands off Canada", "hands off Greenland" and "hands off Ukraine", referencing Trump's changes to US foreign policy. Trump has repeatedly expressed interest in annexing Canada and Greenland. He also got into a public dispute with Ukrainian President Volodymyr Zelensky and has struggled to negotiate a peace deal between Ukraine and Russia.

In Washington DC, thousands of protesters gathered to watch speeches by Democratic lawmakers. Many remarks focused on the role played in Trump's administration by wealthy donors - most notably Elon Musk, who has served as an advisor to the president and spearheaded an effort to dramatically cut spending and the federal workforce.

Florida Congressman Maxwell Frost denounced the "billionaire takeover of our government".

"When you steal from the people, expect the people to rise up. At the ballot box and in the streets," he shouted.

The protests come after a bruising week for the president and his allies. Republicans won a closely watched special Florida congressional election on Tuesday, but with slimmer margins than they had hoped. Wisconsin voters elected a Democratic judge to serve on the state supreme court, roundly rejecting a Musk-backed Republican candidate by almost 10 percentage points.

In both states, Democrats sought to tap into voter anger towards the Trump administration's policies and Elon Musk's influence.

Some polls show approval ratings for President Trump to be slipping slightly.

One Reuters/Ipsos poll released earlier this week found that his approval rating had dropped to 43%, its lowest point since Trump began his second term in January. When he was inaugurated on 20 January, his approval rating was 47%.

The same poll found that 37% of Americans approve of his handling of the economy, while 30% approve of his strategy to address the cost of living in the US.

Another recent poll, from Harvard Caps/Harris, found that 49% of registered voters approve of Trump's performance in office, down from 52% last month. The same poll, however, found that 54% of voters believe he is doing a better job than Joe Biden did as president.

One protester in Washington named Theresa told the BBC that she was there because "we're losing our democratic rights".

"I'm very concerned about the cuts they're making to the federal government," she said, adding that she is also concerned about retirement and education benefits.

Asked if she thought Trump was receiving the protesters' message, she said: "Well, let's see. [Trump has] been golfing just about every day."

Trump held no public events on Saturday, and spent the day golfing at a resort he owns in Florida. He was scheduled to play golf again on Sunday.

The White House released a statement defending Trump's positions, saying he would continue to protect programs such as Medicare and pointing to Democrats as the threat.

"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."

One of Trump's top immigration advisors, Tom Homan, told Fox News on Saturday that protesters held a rally outside of his New York home, but that he was in Washington at the time.

"They can protest a vacant house all they want," Homan said, adding that their presence "tied up" law enforcement and prevented officials from seeing to more important tasks.

"Protests and rallies, they don't mean anything," Homan continued.

"So go ahead and exercise your First Amendment [free speech] rights. It's not going to change the facts of the case."