Donald Trump launched a full-blown attack on Republican arch-rival Ted Cruz on Wednesday, accusing him of stealing victory in Iowa as the Texas senator bit back, rubbishing the mogul's presidential credentials and questioning his sanity.
Fighting back from second place in the Iowa caucus this week, Trump lashed out on Twitter, telling his six million followers that the evangelical conservative had only won the first vote of the 2016 election by fraud.
"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!" Trump wrote.
Cruz fired back a salvo several hours later. "Yet another #Trumpertantrum... @realDonaldTrump very angry w/the people of Iowa. They actually looked at his record," he wrote on his Twitter account.
Trump slammed Cruz for putting out a statement from Iowa saying that a fellow candidate, retired neurosurgeon Ben Carson, was quitting the race, and "lying" to thousands of voters about Trump's policies.
"Based on the fraud committed by Senator Ted Cruz during the Iowa Caucus, either a new election should take place or Cruz results nullified," Trump wrote.
On the campaign trail in New Hampshire, Cruz looked to capitalize on his momentum against the New York billionaire, who leads Republican polls in the Granite State.
"I wake up every day and laugh at the latest thing Donald has tweeted. Because he's losing it," said Cruz. "We need a commander in chief, not a twitterer in chief.
"We need someone with judgment and the temperament to keep this country safe. I don't know anyone who would be comfortable with someone who behaves this way having his finger on the button."
Trump has run a media blitzkrieg campaign, dishing out insults against his political rivals, Mexicans, women and Muslims, sucking the television air time away from every other candidate in the race.
- Iowa loser -
But his Iowa tally -- in second place at just above 24 percent, marginally ahead of Senator Marco Rubio -- in the first vote raises serious questions about whether showmanship has a winning strategy.
A second hiccup, at the New Hampshire primary next Tuesday, would spell political disaster for the reality television star.
Cruz won 27.7 percent of the vote in the Republican caucus in Iowa, staking his claim to be the new standard bearer of the right.
Rubio, whose star has risen in recent weeks, took more than 23 percent, anointing him as the Republican establishment candidate of choice best placed to defeat presumed Democratic nominee Hillary Clinton.
Polls put Trump firmly ahead among Republican voters in New Hampshire, but analysts warn that anything less than a win there will further damage his campaign message that he is a winner.
Jeanne Zaino, a professor of political science in New York, said Trump's outburst -- just his latest -- was a strategic move designed to counter the narrative that he lost in Iowa and that his campaign is beatable.
"That's a huge component of Donald Trump's campaign. He's been campaigning saying he's a winner and all of a sudden he comes out of Iowa a loser," she told AFP.
She predicted that Trump would step up sharp attacks on Cruz and Rubio, the telegenic young senator, as the New Hampshire primary nears.
"It's strategic on his part and he's also trying to make sure that he takes some of the wind out of Cruz and Rubio's sails as he goes into New Hampshire, where he has been leading for some time, to make sure he comes out ahead in New Hampshire," she added.
The Cruz insult ensured once again that Trump headlined the media coverage of the Republican presidential election -- and again saving him from spending millions on campaign advertisements.
"He has said really outlandish things in the past and none of them have really hurt him in the polls. So I don't think this is going to hurt him so much and he's attacking someone whose not wildly popular even in his own party," said Zaino, in reference to Cruz.