NEW YORK, United States (AFP) – Donald Trump went on the offensive yesterday, accusing Republican rival Ted Cruz of stealing victory in Iowa as he sought to burnish his standing ahead of next week’s primary voting in New Hampshire.

The real estate mogul made the sensational accusations on Twitter, telling his six million followers that the first-time senator from Texas had committed fraud in the first caucus of the 2016 US presidential election.

“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.

He criticised Cruz for putting out a statement saying that a fellow candidate, retired neurosurgeon Ben Carson, was quitting the race, and accused Cruz of 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.

The accusations, the latest in a long line of Trump insults aimed at his rivals, come in stark contrast to his gracious concession speech in Iowa on Monday, saying he was “honoured” to finish second.

His tally – just above 24 per cent, for second place after Cruz and just ahead of Senator Marco Rubio – in the first vote after months of wall-to-wall media coverage, 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 billionaire.

Cruz won 27.7 per cent 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, won more than 23 per cent, 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 in Tuesday’s primary 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 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 Wednesday that Trump headlined the media coverage of the Republican presidential election – and once 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 who’s not wildly popular even in his own party,” said Zaino, in reference to Cruz.

Rick Wilson, a Republican consultant who thinks Rubio is the Republican candidate best placed to win the White House, said the billionaire’s latest outburst was a sign of desperation.

“I don’t think T’s meltdown today is helping his campaign,” he told AFP. “It’s so petulant and childish. He should be talking to New Hampshire voters. Instead he’s yelling at Iowa for not giving him a first-place finish.”