From London and Paris to New York and Washington, thousands of people took to the streets to protest US President Donald Trump's travel ban amid a fierce legal battle over the order.
The biggest demonstration by far on Saturday took place in the British capital, where an estimated 10,000 people turned out, chanting "Theresa May: Shame on You" to denounce the British prime minister's support for the new US leader.
Brandishing placards declaring "No to scapegoating Muslims" and "Socialism not Trumpism," the protesters marched from the US embassy toward May's Downing Street office.
In an executive order issued on January 27, Trump slapped a blanket ban on nationals of seven mainly Muslim countries -- Iran, Iraq, Libya, Somalia, Sudan, Syria and Yemen -- barring their entry to the United States for 90 days.
Refugees were also barred from entry for 120 days, except those from Syria, who were blocked indefinitely.
On Friday, a US federal judge temporarily suspended the ban, a move which the Republican president vowed to fight.
Late Saturday, the Justice Department appealed the block on the travel ban but a federal appeals court rejected any immediate move to reinstate it.
"We'll win. For the safety of the country, we'll win," Trump told reporters ahead of the appeals court decision.
About 3,000 people demonstrated in Trump's hometown of New York where protests against the property magnate-turned-world leader take place almost daily.
Activists and supporters gathered outside the Stonewall Inn, a landmark of the gay rights movement in Greenwich Village, to show support for Muslims and others affected by Trump's immigration order.
Democratic Senate minority leader Charles Schumer led the crowd -- which carried rainbow flags and Americans flags -- in cheers of "Dump Trump."
In Washington, hundreds marched from the White House to Capitol Hill.
"Donald, Donald can't you see, we don't want you in DC," chanted the demonstrators in the largely Democratic-leaning US capital.
"I was born and raised here and for the first time in my life, I don't feel safe," said Abu Bakkar, 26, whose parents are originally from Pakistan.
The Department of Defense consultant said the new president "has revealed hate that's been underground for so long. He has divided one of the greatest countries in the world."
At least 2,000 people marched near Trump's Florida golf club as the president and First Lady Melania Trump attended a Red Cross gala at his Mar-a-Lago estate.
"You know, my father fought World War II," protestor Rob Resaid said. "For years and years, so many people fought for freedom in this country and now it's being taken away."
"We have to stand now before all of our rights are taken away, before we become the pariah of the world."
In Britain, more than 1.8 million people have signed a petition saying Trump should not be afforded a formal state visit because it would embarrass Queen Elizabeth II.
"We're going to bring this capital to a halt on the day he comes over. We are going to make it impossible for him to have a state visit," Chris Nineham, vice-chair of the Stop the War Coalition, told AFP.
The Guardian newspaper said around 10,000 people attended the London protest, while organisers claimed 40,000.
Elsewhere in Europe, about 1,000 people turned out in both Paris and Berlin, while smaller gatherings of several hundred people took place in provincial British cities including Manchester and Birmingham.
"We are here to say we don't accept hate," said 20-year-old American Michael Jacobs, co-organizer of the Paris rally, surrounded by signs saying "Refugees are welcome!"
In Berlin, protesters rallied in front of the Brandenburg Gate.
"I hope they will change something, but I am really disappointed," said Mahsa Zamani, a 26-year-old Iranian medical student who had been due to head to a Florida hospital for an internship.
"It is still discrimination, and I don't know if I really feel like going even if they are changing (the rules)."
In Hong Kong, hundreds of expatriate workers marched through the city center on Sunday to protest the "tyrannical and fascist" ban, in the Asian hub's first major protest against Trump.
Many were women from the Philippines and Indonesia employed in Hong Kong as domestic workers. Protesters chanted, "US imperialist, number one terrorist!"
"We are very worried that what Donald Trump is doing will also be adopted by other states who believe that their nation is the greatest nation without the migrants," activist and domestic worker Eni Lestari said outside the US Consulate General.