Ted Cruz fired back at Donald Trump Wednesday over allegations that he “stole” the Iowa election, accusing the billionaire businessman of throwing a “Trumpertantrum” and questioning whether he has the “temperament” to lead.

Speaking to reporters in New Hampshire, Cruz quipped that with Trump in charge, Americans might wake up and find he’s “nuked Denmark.”

“It seems his reaction to everything is to throw a fit,” the Republican presidential candidate said, adding: “He’s losing it.”

The tough response came after Trump unleased a hail of tweets accusing the Texas Republican senator of cheating in the Iowa caucuses -- calling for either a new election to be held or the results to be nullified.

He was referring to accusations from candidate Ben Carson that Cruz supporters falsely told caucus-goers the retired neurosurgeon was suspending his campaign, as well as a controversial Cruz mailer that accused Iowans of a “voting violation.”

"It was a fraud as far as I'm concerned," Trump told Fox News' Greta Van Susteren Wednesday evening. "I think what he did is disgusting. He said that Ben Carson, who's a fantastic guy, had dropped out."

Trump also claimed “he cheated,” tweeting: “Ted Cruz didn't win Iowa, he stole it. That is why all of the polls were so wrong and why he got far more votes than anticipated. Bad!”

Carson, meanwhile, added fuel to the debate as he escalated accusations Wednesday that Cruz supporters spread false rumors on caucus night that he was suspending his campaign.

At a Washington press conference on Wednesday afternoon, Carson said the Cruz campaign tried to “distort” information and claimed the interference impacted the outcome of the race.

Interviewed earlier on Fox News’ “Hannity,” Cruz apologized to Carson.

He said his political team had forwarded an initial CNN news report saying Carson was taking a break from the campaign trail, but did not forward an update to that same story.

“Unfortunately, they did not then forward the subsequent story, that was Ben’s campaign clarifying that he was continuing the campaign and was not canceling the campaign,” Cruz said. “And so I apologize to Ben for that. They should have forwarded that subsequent story. That was a mistake on our part.”

Carson told Fox News on Wednesday that while he accepts Cruz’s apology, “the question is what’s being done about it.” Carson suggested Cruz may be trying to “brush it under the rug.”

Early reports that Carson – who was directly competing with Cruz for social conservative and evangelical supporters – was leaving the campaign trail started to surface as caucusing began Monday evening. Upon hearing reports that their candidate was leaving the trail to return to his home in Florida, Team Carson responded swiftly, saying the retired neurosurgeon was only going home for clean clothes but was then headed to New Hampshire for the Feb. 9 primary.

But Carson said Cruz supporters and representatives took that narrative a step further, and told caucus-goers at “many” precincts that he was dropping out.

Carson finished a distant fourth in Iowa.

The Cruz campaign also took heat for campaign literature it sent out to potential voters before caucus night that seemingly accused them of voting violations over low voter turnout – and urged them to caucus Monday to improve their “score.”

Spokesman Rick Tyler earlier told MSNBC that Iowans are used to getting similar ones and that the campaign “modeled ours after them.”