Donald Trump defended himself on Twitter Saturday against criticism that he did not challenge a questioner at a recent town hall meeting who suggested the U.S. should “get rid” of Muslims and claimed that President Obama is a Muslim born outside of the United States.

“We have a problem in this country, it’s called Muslims,” said the questioner in the audience at the New Hampshire town hall meeting on Thursday. “Our current President is one. We know he’s not even an American,” he added. “We have training camps growing where they want to kill us. That’s my question, when can we get rid of them?”

“We’re going to be looking at a lot of different things,” Trump said. “You know, a lot of people are saying that and a lot of people are saying that bad things are happening. We’re going to be looking at that and many other things.”

After the meeting, Trump did not answer questions from reporters about why he didn’t challenge the comments, according to CNN. But Trump’s campaign manager, Corey Lewandowski, later told the network that Trump didn’t hear the accusation that Obama was a Muslim.

“All he heard was a question about training camps, which he said we have to look into,” Lewandowski told CNN. “The media want to make this an issue about Obama, but it’s about him waging a war on Christianity.”

On Twitter today, Trump addressed the comments, questioning why he was expected to defend Obama from his supporter’s remarks:

Am I morally obligated to defend the president every time somebody says something bad or controversial about him? I don't think so!

— Donald J. Trump (@realDonaldTrump) September 19, 2015

This is the first time in my life that I have caused controversy by NOT saying something.

— Donald J. Trump (@realDonaldTrump) September 19, 2015

If someone made a nasty or controversial statement about me to the president, do you really think he would come to my rescue? No chance!

— Donald J. Trump (@realDonaldTrump) September 19, 2015

If I would have challenged the man, the media would have accused me of interfering with that man's right of free speech. A no win situation!

— Donald J. Trump (@realDonaldTrump) September 19, 2015

Trump’s failure to challenge the comments drew strong criticism from Democratic candidates Hillary Clinton, Bernie Sanders and Martin O’Malley. Republican candidate Chris Christie also said Trump had handled the situation poorly.

“I would just tell you that if somebody at one of my town hall meetings said something like that, I would correct them and say, now, the president’s a Christian and he was born in this country,” Christie said on NBC’s TODAY show Friday. “Those two things are self evident.”

This article originally appeared on Time.com

For more about Donald Trump, watch this Fortune video: