'Worse than Voldemort': Trump's call for Muslim ban slammed by Harry Potter author JK Rowling.

Donald Trump has launched a staunch defence of his proposal to ban Muslims from entering the United States amid a storm of criticism, with Harry Potter author JK Rowling labelling him worse than her fictional villain Voldemort and the White House painting him as a “carnival barker” with “fake hair”.

Mr Trump, who is the Republican presidential front-runner, called for a “complete and total shutdown of Muslims entering the country”, claiming there was “great hatred towards Americans by large segments of the Muslim population”.

The remarks sparked condemnation from both sides of US politics, as well as world leaders and the United Nations' refugee agency, while social media users compared Mr Trump to Voldemort.

Rowling responded to the comparison, saying: "How horrible, Voldemort was nowhere near as bad."

The White House challenged Republicans to denounce Mr Trump, saying his campaign had a "dustbin of history" quality and labelling his proposals unconstitutional.

"What Donald Trump said yesterday disqualifies him from serving as president," White House spokesman Josh Earnest said, describing Mr Trump's comments variously as "offensive" and "toxic."

"What he said is disqualifying and any Republican who's too fearful of the Republican base to admit it has no business serving as president either."

Mr Trump dismissed the growing outrage in a lengthy interview, comparing his plan to the World War II detainment of Japanese-Americans.

He said his ideas were no worse than those of then-US president Franklin D Roosevelt, who oversaw the internment of more than 110,000 people in US government camps after Japanese forces bombed Pearl Harbor on December 7, 1941.

"What I'm doing is no different than FDR," Mr Trump told ABC America.

Mr Trump warned repeatedly that an attack on the scale of September 11, 2001, could happen again if officials did not act first.

"We have no choice but to do this. We have people that want to blow up our buildings, our cities," he said.

"We have to figure out what's going on."

Mr Trump said people would be asked about their religion at US borders and that the ban would extend to Muslim leaders of other nations. He said he would not support internment camps.

The real estate mogul's comments drew criticism from as far afield as London and Cairo, where Egypt's official religious body Dar al-Iftaa denounced his comments as "extremist and racist".

A spokeswoman for British prime minister David Cameron said he "completely disagrees" with Mr Trump's remarks, which were "divisive, unhelpful and quite simply wrong".

The real estate mogul was also lambasted by leading Republicans and campaign rivals.

"Donald Trump is Hillary Clinton's Christmas gift wrapped up under a tree," Republican presidential candidate Carly Fiorina said on Twitter.

'Tell Donald Trump to go to Hell'

Senator Lindsey Graham said Mr Trump was succeeding only in fuelling the radical ideology of the Islamic State (IS) group.

"Do you know how you win this war? You side with people in the faith who reject this ideology, which is 99 per cent," he told CNN, before invoking Mr Trump's campaign slogan - "make America great again".

"And do you know how you make America great again? Tell Donald Trump to go to Hell."

Other Republican presidential contenders including Marco Rubio, John Kasich, Chris Christie and Jeb Bush, as well as Republican House speaker Paul Ryan, also swiftly rejected Mr Trump's proposal.

Mr Bush said was Mr Trump "unhinged", while Mr Rubio said the comments were "offensive and outlandish".

Hillary Clinton, the Democratic presidential frontrunner, said Trump was playing "right into the hands of terrorists" and Rick Kriseman, the Democratic mayor of Saint Petersburg, Florida, tweeted: "I am hereby barring Donald Trump from entering St. Petersburg until we fully understand the dangerous threat posed by all Trumps."

US secretary of state John Kerry said: "Comments such as those that we just heard are not constructive, and that is putting it diplomatically."

Bernie Sanders, another Democrat presidential hopeful, said the comments were racist and divisive.

"The United States is a great nation when we stand together. We are a weak nation when we allow racism and xenophobia to divide us," he said.

Dick Cheney, former Republican vice-president under George W Bush, said banning Muslims would go against everything the US stood for.

UNHCR spokeswoman Melissa Fleming, asked about Mr Trump's remarks, said they could endanger the program for resettling Syrian refugees in the US.

"What the candidate you are speaking of was speaking of was an entire population but this also impacts the refugee program," she said.

About 100,000 refugees are resettled worldwide each year, including to the US, the largest recipient under the UNHCR's program.

"The [Obama] administration has been standing by the program. This is most scrutinised population coming into the United States," she added.

Up to 40 US governors had spoken out against the resettlement program, the UNHCR said.

"We are concerned that the rhetoric that is being used in the election campaign is putting an incredibly important resettlement program at risk that is meant for the most vulnerable people — the victims of the wars that the world is unable to stop," Ms Fleming said.

This post originally appeared on the ABC and was republished here with full permission. 

© 2015 Australian Broadcasting Corporation. All rights reserved. Read the ABC Disclaimer here.