Trump on Cruz: "A Little Bit of a Maniac"

^{Editor's note: This story has been updated throughout.}

Donald Trump is expanding his criticism of  Ted Cruz, once his closest ally in the Republican race for the White House.

In TV appearances Sunday morning, the billionaire left little doubt the detente is over, bluntly questioning the Texas senator's temperament to lead the nation and his ability to get along with others. 

“I don’t think he’s qualified to be president because I don’t think he has the right temperament," Trump said in an interview on Fox News Sunday. "Well, you look at the way he’s dealt with the Senate, where he goes in there like a — you know, frankly, like a little bit of a maniac."

“You can't walk into the Senate and scream and call people liars and not be able to cajole and get along with people," Trump later added, apparently referring to Cruz's clash earlier this year with Senate Majority Leader Mitch McConnell. "He’ll never get anything done, and that’s the problem with Ted."

Trump also directly responded to the source of the new tension between the two candidates: a report Thursday that Cruz had raised questions about Trump's "judgment" at a fundraiser.

"I would say I have far better judgment than Ted," Trump said in an interview on CNN's State of the Union, citing as examples his business success and opposition to the war in Iraq. 

Cruz's campaign declined to comment on Trump's remarks Sunday morning, but the senator made light of the attack later in the day on Twitter. Cruz shared a link to the song "Maniac" by Flashdance, dedicating it to "my friend [Trump] and good-hearted #Maniacs everywhere."

Trump's widened criticism came two days after he launched his first attacks on Cruz, suggesting at a rally in Iowa that the senator is beholden to the oil industry. Cruz has not responded to the allegation, but Trump suggested a confrontation isn't far off.  

“Look, I expect to get it on because I’m leading by a lot. I’m leading him by a lot," Trump said, later adding that he believes Cruz can only maintain his friendly posture for so long. "I think the time will come to an end pretty soon, it sounds like."

Trump's offensive against Cruz is unfolding as the senator rises in the polls, soaring to a 10-point lead in Iowa, according to a Des Moines Register survey released Saturday. Summing up its findings, the newspaper said it found Cruz was stronger than his closest competitors on qualities including have the "right temperament."

On Sunday morning, two more polls showed Cruz gaining on Trump: a NBC News/Wall Street Journal survey that found Cruz surging to within 5 points of Trump nationally and a Fox News survey that puts Cruz 2 points ahead of Trump in Iowa.