MOUNT PLEASANT, S.C. — Donald Trump on Tuesday stood by his call to block all Muslims from entering the United States, even as the idea was widely condemned by rival Republican presidential candidates, party leaders and others as un-American.

“I don’t care about them,” Trump told CNN when asked about denunciation of the idea by GOP leaders. “I’m doing what’s right.”

He defended his plan for a “total and complete shutdown of Muslims entering the United States” by comparing it with President Franklin Roosevelt’s decision to intern Japanese Americans during World War II.

“This is a president who was highly respected by all,” Trump said Tuesday. “If you look at what he was doing, it was far worse.”

The idea announced by Trump Monday evening drew swift rebukes, some from abroad. British Prime Minister David Cameron slammed it as “divisive, unhelpful and quite simply wrong.” Muslims in the United States and around the world denounced the idea unconstitutional or offensive.

House Speaker Paul Ryan told his Republican colleagues that Trump’s comments on Muslims is “not who we are” as a party or American people.

The front page of the Philadelphia Daily News pictured Trump holding his right hand out as if in a Nazi salute with the headline “The New Furor.” In morning TV interviews Tuesday on ABC and CNN, Trump was asked about being compared to Hitler.

The candidate didn’t back down, saying that banning all Muslims “until our country’s representatives can figure out what the hell is going on” is warranted after attacks by Muslim extremists in Paris and last week’s shooting in San Bernardino, California, that killed 14.

“We are now at war,” Trump said, adding: “We have a president who doesn’t want to say that.”

Trump’s proposed ban would apply to immigrants and visitors alike, a sweeping prohibition affecting all adherents of a religion practiced by more than a billion people worldwide.

Trump announced his plan to cheers and applause at a Monday evening rally in South Carolina.

“Until we are able to determine and understand this problem and the dangerous threat it poses, our country cannot be the victims of horrendous attacks by people that believe only in jihad, and have no sense of reason or respect for human life,” Trump said in a written statement explaining his position.

At the rally he referred to the 9/11 attacks, warning that without drastic action, “it’s going to get worse and worse, you’re going to have more World Trade Centers.”

Rod Weader, a 68-year-old real estate agent from North Charleston who attended the rally and said he agreed with Trump’s plan “150 percent.”

“As he says, we have to find out who they are and why they are here,” he said.

Since the Nov. 13 attacks in Paris that killed 130 people and wounded hundreds more, a number of Republican presidential contenders have proposed restrictions on Syrian refugees — with several suggesting preference for Christians seeking asylum — and tighter surveillance in the U.S.

But Trump’s proposed ban goes much further, and his Republican rivals were quick to reject the latest provocation from a candidate who has delivered no shortage of them. “Donald Trump is unhinged,” Jeb Bush said via Twitter. “His ‘policy’ proposals are not serious.”

John Kasich slammed Trump’s “outrageous divisiveness,” while a more measured Ted Cruz, who has always been cautious about upsetting Trump’s supporters, said, “Well, that is not my policy.”