US President Donald Trump has defended his executive action curbing immigration from seven predominantly Muslim countries, amid growing criticism that the measures are discriminatory and divisive.

Key points: Trump says executive order about safety, not religion

Trump says executive order about safety, not religion White House says order "perhaps" should have been wider

White House says order "perhaps" should have been wider British PM orders senior ministers to call US counterparts in protest

British PM orders senior ministers to call US counterparts in protest Germany, France and Indonesia also voice concern

Governments from London and Berlin to Jakarta and Tehran have spoken out against the move, which sparked havoc and protests at airports over the weekend, with some US-bound passengers turned away and others detained.

Mr Trump issued a statement reiterating that the order, which was partially blocked by a federal judge's ruling that stranded travellers could stay in the country, was "not a Muslim ban, as the media is falsely reporting".

"This is not about religion — this is about terror and keeping our country safe," he said, adding his policy was "similar to what President Obama did in 2011 when he banned visas for refugees from Iraq for six months".

Mr Trump said the countries affected — Iran, Iraq, Libya, Somalia, Sudan, Syria and Yemen — had previously been identified by the Obama administration as being "sources of terror".

"We will again be issuing visas to all countries once we are sure we have reviewed and implemented the most secure policies over the next 90 days," he said, adding that he had "tremendous feeling for the people involved in this horrific humanitarian crisis in Syria".

The President said America was "a proud nation of immigrants" and would "continue to show compassion to those fleeing oppression".

"But we will do so while protecting our own citizens and border," he added.

Mr Trump's chief of staff, Reince Priebus, had earlier defended the implementation of the action.

"It wasn't chaos," he said on NBC's Meet the Press program, adding that 325,000 travellers entered the US on Saturday (local time) and 109 of them were detained.

"Most of those people were moved out. We've got a couple dozen more that remain and I would suspect that as long as they're not awful people that they will move through before another half a day today."

Asked why nations like Saudi Arabia, Afghanistan, Pakistan and Egypt were not included in the banned list, Mr Priebus said: "Perhaps other countries needed to be added to the executive order moving forward."

Growing global backlash

Sorry, this video has expired Activists protest Trump's 'racist, unconstitutional' ban on Muslim-majority nationals entering the US

The order drew criticism from senior Republican senator John McCain, who warned it could serve as propaganda for terrorists, and Canada, which offered temporary residency to stranded travellers.

British Prime Minister Theresa May ordered two of her most senior ministers, Foreign Secretary Boris Johnson and Home Secretary Amber Rudd, to call their US counterparts in protest.

Britons affected by the ban include decorated Olympian Sir Mo Farah, who was born in Somalia.

German Chancellor Angela Merkel also spoke out against the ban, saying the fight against terrorism was no excuse for banning refugees.

"She is convinced that even the necessary, resolute fight against terrorism doesn't justify putting people of a particular origin or particular faith under general suspicion," spokesman Steffen Seibert said.

Ms Merkel raised the issue during a phone call with Mr Trump on Saturday, citing the 1951 Geneva Refugee Convention that calls on signatories to take in people fleeing war, Mr Seibert said.

"The German Government will now examine what consequences the US Government's measures have for German citizens with dual citizenship and, if necessary, represent their interests toward our American partners," he said.

Canadian Prime Minister Justin Trudeau said his country welcomed those fleeing war and persecution, "regardless of your faith".

Sorry, this video has expired Spicer says immigration ban will keep Americans safe

Among the first leaders to voice criticism was French President Francois Hollande, who said that "when [Mr Trump] rejects the arrival of refugees, while Europe has done its duty, we should respond to him".

Italian Prime Minister Paolo Gentiloni said "open society, plural identity, no discrimination" were the "pillars of Europe", while the Danish, Swedish and Norwegian governments also registered their opposition.

The order also stirred angry reactions in Iraq, one of the countries listed, where more than 5,000 US troops are deployed to help Iraqi and regional Kurdish forces in the war against Islamic State insurgents.

Some members of parliament said Iraq should retaliate with similar measures against the US.

"Iraq is in the front line of the war on terrorism ... and it is unfair that the Iraqis are treated in this way," Parliament's foreign affairs committee said in a statement.

Meanwhile Indonesia, the country with the world's biggest Muslim population, warned the measures would make it harder to fight terrorism around the globe.

Indonesia has told its citizens living in the US to remain calm and inform themselves about their civil rights by reading the American Civil Liberties Union (ACLU) website.

'No-one is to be removed'

The US ban affects travellers with passports from Iran, Iraq, Libya, Somalia, Sudan, Syria and Yemen. According to State Department guidance, travellers with dual nationality will also be affected.

Sorry, this video has expired Trump says America should have had 'extreme vetting' for many years

But the order was partially stayed by an emergency court ruling, in response to a case filed by the ACLU on behalf of Iraqi men Hameed Khalid Darweesh, who had been an interpreter for the US military, and Haider Sameer Abdulkhaleq Alshawi.

The ruling, by Judge Ann Donnelly of a US District Court in New York, was cheered at Boston's Logan International Airport — one of several major US airports where protesters angry with Mr Trump's order gathered.

"I am directing the Government to stop removal if there is someone right now in danger of being removed," she said in the court hearing.

"No-one is to be removed in this class."

The next hearing in the case was set for February 10.

Mr Trump had promised during his campaign what he called "extreme vetting" of immigrants and refugees to try to prevent terror attacks.

Protests have continued across the country. ( AP: Elaine Cromie )

Reuters/AP