Tens of thousands of people have rallied in cities and airports across the US to voice outrage over President Donald Trump's executive order restricting entry into the country for travellers from seven Muslim-majority nations.
In New York, Washington and Boston, a second wave of demonstrations followed spontaneous rallies that broke out at US airports on Saturday as US Customs and Border Protection agents began enforcing Mr Trump's directive.
The protests spread westward as the day progressed.
The order has led to the detention or deportation of hundreds of people arriving in the United States.
Sixteen state attorneys general have said the order is unconstitutional. Several federal judges have temporarily halted the deportation of visa holders.
Protests are planned across Britain, with marches scheduled in London, Edinburgh, Cardiff and Manchester. Those will add to pressure on Britain's prime minister Theresa May to axe Mr Trump's state visit.
Canada has offered temporary residency to any travellers stranded the orders.
Big companies such as Apple, Google and Microsoft offered legal aid to employees affected by the order, in letters sent to staff.
Several Silicon Valley executives donated to legal efforts to support immigrants facing the ban.
Trump defends order
In a written statement Mr Trump accused the media of falsely reporting that his order amounted to a ban on Muslims.
He said the United States would resume issuing visas to all countries once "secure policies" were put in place over the next 90 days.
"To be clear, this is not a Muslim ban, as the media is falsely reporting," Mr Trump's statement said. "This is not about religion - this is about terror and keeping our country safe."
White House press secretary Sean Spicer said there would be no backdown on the order, arguing that only a small percentage of people had been affected so far.
"Let's look at the facts of what happened, there's 325,000 people from foreign countries who travelled into the United States yesterday. There were 109 people that this actually addressed that had come in post-entry that have come in from the seven countries that we've identified."
Trump's order 'un-American'
One of the largest of Sunday's protests took place at Battery Park in lower Manhattan, within sight of the Statue of Liberty in New York Harbor, long a symbol of welcome to US shores.
Democratic Senator Charles Schumer of New York told the crowd that Mr Trump's order was un-American and ran counter to the country's core values.
"What we are talking about here is life and death for so many people," the Senate Democratic leader said. "I will not rest until these horrible orders are repealed."
The march, estimated to have grown to about 10,000 people, later began heading to the US Customs and Border Protection office in lower Manhattan.
In Washington, thousands rallied at Lafayette Square across from the White House, chanting: "No hate, no fear, refugees are welcome here."
It was the second straight weekend that Washington was the scene of protests. The previous Saturday, hundreds of thousands of people participated in a rally and march in support of women's rights, one of dozens staged across the country.
On Sunday, many of the protesters left the White House area and marched along Pennsylvania Avenue, stopping at Trump International Hotel where they shouted: "Shame, shame, shame."
A crowd that police estimated at 8000 people eventually arrived at the steps of the US Capitol, where a line of uniformed officers stood guard.
About 200 protesters chanted on Sunday afternoon at Washington Dulles International Airport in northern Virginia near the US capital.
About the same number gathered at New York's John F. Kennedy International Airport, where anxious families awaited relatives detained for hours after flights from countries affected by the presidential order.
At Los Angeles International Airport, hundreds of people had gathered to protest Trump's order, as chants of "refugees are welcome here" echoed through the arrivals hall.
Organisers estimated that more than 10,000 people packed Boston's Copley Square to hear Senator Elizabeth Warren of Massachusetts, a vocal critic of Mr Trump and a leader of the Democratic Party's liberal wing, and other speakers.
During the protests, dozens of Muslims, some of them kneeling on protest signs, bowed in prayer on rugs laid out on a grassy patch of ground in the square.
In Houston, which was already filling up with visitors for next Sunday's Super Bowl, about 500 people marched through the downtown.
'Jews should be the first ones to defend Muslims'
Jennifer Fagen, 47, a sociology professor at Lamar University in Beaumont, Texas, said she hoped she did not lose her job for protesting.
"I'm Jewish, and it's supposed to be 'never again,'" Fagen said, referring to the Holocaust. "Jews should be the first ones to defend Muslims, considering what has happened to us, and it seems it's being repeated under Trump."
At Detroit Metropolitan Airport, police cordoned off sections of terminal as up to 3000 demonstrators chanted, "No hate, no fear, refugees are welcome here."
Among the demonstrators were Wail Aljirafi and his wife, Samyeh Zindani of Ann Arbor, Michigan, and their three children.
"We want them to feel that they're always included," Zindani, a Yemeni-American, said.
In the Detroit suburb of Hamtramck, Michigan, home to a large number of Yemeni immigrant families and the nation's first Muslim-majority city council, at least 600 people rallied outside City Hall.
Rama Alhoussaini, 23, a Syrian immigrant who lives in nearby Dearborn, said she and her family emigrated to Michigan in 1999 when she was 6 years old.
"Now for us to see this kind of hatred and bigotry, it breaks my heart," she said. "It makes me feel like I am not wanted here."
Meanwhile Canada's Immigration Minister Ahmed Hussen told a news conference he wanted to assure anyone stranded in Canada that he would use his authority as minister to provide them with temporary residency if needed.
The government of Liberal Prime Minister Justin Trudeau refrained from criticising the US, which takes 75 percent of Canadian exports, preferring instead to stress Canada was open to refugees.