Republican presidential candidate Donald TrumpDonald TrumpTrump haunts McCain's reelection fight Quinnipiac pollster: 'Red flags' in Trump campaign Trump will begin campaigning in communities of color MORE on Tuesday accused rival Ted CruzTed CruzTrump haunts McCain's reelection fight The Trail 2016: On the fringe FULL SPEECH: Hillary Clinton links Trump to 'alt-right' in Reno MORE of having “a mental problem.”
“Seriously, he’s got a mental problem,” Trump told host Maria Bartiromo on Fox Business Network’s "Mornings with Maria."
Trump said Cruz is misleading Americans about Trump's fundamental policy positions on hot-button topics including gun control and healthcare.
“He will say I’m against the Second Amendment,” he said. “He will say I’m terribly in favor of ObamaCare, which is ridiculous. These are things that are staples of what I'm about.
"I’m totally in favor of the Second Amendment. ... I want the Second Amendment — I’d strengthen it if anything."
Trump added that other GOP White House hopefuls have slammed Cruz for dishonesty.
“By the way, I’m not the only that said it,” he said. "Marco RubioMarco RubioLatino Republicans split on Trump's outreach Illegal immigration foe: Trump shift the 'death knell of his candidacy' Analysis: Clinton speaks at higher grade level than Trump MORE called him a liar during the debate.”
Cruz has repeatedly accused Trump and Rubio of not being sufficiently conservative. He accused both men on Monday of shouting “liar” at critics anytime their actual beliefs are put in the spotlight.
“It is not being honest or candid for either Marco Rubio or Donald Trump to pretend that their records are different than what they are and simply yell and scream at anyone who points to the words that have come out of their own mouths,” Cruz said.