At his first public appearance since Wednesday’s GOP primary debate, Republican front-runner Donald Trump on Thursday fielded a question from a supporter in New Hampshire about Muslim extremism. The issue? The questioner described Muslims as a “problem in this country,” before adding, “you know our president is one” – and Trump just let it slide.

Donald Trump not denouncing false statements about POTUS & hateful rhetoric about Muslims is disturbing, & just plain wrong. Cut it out. -H — Hillary Clinton (@HillaryClinton) September 18, 2015

Thursday’s questioner went on to ask what Trump would do to curb the growth of extremist training camps. “We’re going to be looking into that,” the real estate mogul responded. Pressed by MSNBC to elaborate, Trump said, ”Christians need support in this country. Their religious liberty is at stake.”

A campaign spokeswoman said Trump interpreted the man to be asking about getting rid of the alleged “training camps,” not Muslims.

Trump’s reaction was quickly criticized by Hillary Clinton, who called his response “disturbing,” and by New Jersey Gov. Chris Christie, who told “TODAY” Friday morning that he “wouldn’t have permitted that” if he were faced with the same situation. “I would correct him. I’d say that the president’s a Christian and he was born in this country. Those two things are self-evident.”

Vermont Sen. Bernie Sanders also weighed in, tweeting that “Trump must apologize to the president and American people for continuing the lie that the president is not an American and not a Christian” and “This nonsense has got to end.”

“Let’s stop the racism. Let’s stop the xenophobia,” he added in another tweet.

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Trump’s failure to correct the record about Obama’s religion stands in contrast to former Republican presidential candidate Sen. John McCain, who was repeatedly booed by a crowd at a 2008 town hall event in Minnesota for contradicting a woman who described Obama as “an Arab.”

Trump, who has been leading by double-digits in national polls, began Thursday’s town hall in classic Trump form, citing numerous surveys from TIME, Newsmax, and Slate showing he won Wednesday night’s Republican debate in California, and referencing well-attended events he’s held around the country.

Trump, who has long criticized politicians for accepting campaign donations, vowed for what appeared to be the first time that, if elected, he would not accept a salary.

This nonsense has got to end. — Bernie Sanders (@BernieSanders) September 18, 2015

The real estate mogul also boasted about earning the endorsement of New England Patriots star Tom Brady – “when you get Tom, you’re getting a champ and he’s a great champ” — and claimed that CNN had treated him “a little bit better” than Fox News, which hosted the first Republican debate.

Trump appeared to delight in a question about rival Carly Fiorina.

“She did a terrible job at Lucent. She did a terrible, terrible, terrible job at Hewlett-Packard. The stories that have been written about it are legendary,” Trump said. “I don’t see how she’s going to be able to get over that hurdle.”

For the most part, however, Trump stuck to his usual talking points, rattling off the debt the U.S. owes China and Japan, and vowing once again to be the “greatest jobs president God has ever created.”

On immigration, Trump’s primary solution remained the construction of a wall along America’s border with Mexico. He dismissed criticism that such a barrier would cost $10 to $12 billion.

“You ask Israel if a wall works,” he said before going on to reference the Great Wall of China as an example of success. Trump added that there would be “a nice opening” in the wall for those who wanted to enter the country legally – a refrain similar to one he sang at Wednesday’s debate. The candidate, who also vowed to save Social Security and repeal Obamacare, smiled when an attendee described it as the “Trump wall.”

Because his name would be associated with it, he insisted, “I’ve got to make it beautiful — big and powerful and beautiful.”