Gov. Chris Christie (N.J.) is rejecting fellow GOP candidate Donald TrumpDonald TrumpTrump: 'I'll be so angry' if healthcare reform doesn't pass Trump offers his own rating of media's '100 days' Pence: Media ignoring facts and 'spreading that fake news' MORE’s memory of Muslim Americans in New Jersey celebrating on 9/11.
Christie earlier said he did not "recall" celebrations in parts of New Jersey with strong Arab communities, in comments Trump referred to as "very weak."
During Monday night's interview, the New Jersey governor defended his initial reaction.
“I was not focused on everything else that was going on in New Jersey that day,” Christie said.
“My wife and my brother were trapped in lower Manhattan, and I didn’t know if they were dead or alive,” he continued. “I said, ‘I don’t think it happened,’ but I had to put that qualifier in there."
“Everybody knows that it didn’t happen, so what’s the use of joining the cacophony?” Christie added of Trump’s 9/11 claims.
Christie also criticized Trump for apparently mocking a disabled reporter during a campaign rally late last month. Trump sparked outrage when he taunted journalist Serge Kovaleski, who suffers from arthrogryposis, a chronic condition afflicting his arms.
“He shouldn’t be making fun of people with disabilities,” Christie said. "It’s just not worthy of someone running for the president of the United States."
“He’s got to answer for himself,” he added of Trump. "Part of the folly of all this is that we’re answering for him. He’s said what’s he’s said, and now the people who vote will have to judge him. In the context of Donald, outrageous is a high bar.”
Trump has repeatedly said he was unaware of Kovaleski’s condition before mocking the reporter.
Christie also said he would have no problem confronting Trump.
"If Donald Trump starts screaming at me in the middle of a speech, you can be sure I’ll say, ‘sit down and shut up.’ "
"I will do what I think is best to win this race,” the Republican White House hopeful added. "I’m in it to be the next president of the United States. The stakes are too high to have a vanity race.”