It is the first day of voting since Mitt Romney's attack on Trump, and he seems to have had an effect

Ted Cruz launched a spectacular comeback on Super Saturday, crushing Donald Trump in two states while the tycoon only narrowly won in two others where he was projected to be well ahead.

Cruz won Kansas with 48 per cent to Trump's 23 per cent and Maine by 46 per cent to Trump's 33 - and although he'd always been predicted to do well in the Midwest, his victory in the North East is a surprise.

Meanwhile, Trump won with a slim majority of three per cent in Louisiana and four per cent in Kentucky - both states where he had been polling well.

It was a terrible night for Marco Rubio, who came third in all races except Maine where he finished dead last.

Both Trump and Cruz called for him to drop out of the race following his abysmal performance.

Trump said: 'I think Marco Rubio had a very bad night and personally I'd call for him to drop out of the race. I think it's time.'

While Cruz added: 'People recognize that if we're divided Donald wins, and if Donald wins, Hillary wins.'

'The scream you hear, the howl that comes from Washington DC, is utter terror at what we the people are doing together,' he added after his Kansas victory in Coeur d'Alene, Idaho.

Saturday was the first round of votes and primaries since Mitt Romney made a dramatic intervention in the race for the Republican nomination, urging this party not to make Trump the nominee.

And it seems he's made a difference, narrowing Trump's lead and giving Cruz a boost. The GOP establishment's preferred candidate Rubio, however, seems beyond help.

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Ted Cruz, pictured at a rally Saturday in Coeur d'Alene, Idaho, crushed Trump in Kansas and Maine and said in his victory speech it would be a disgrace if the billionaire were the GOP's presidential nominee

Earlier on Saturday, Cruz also won in Kansas with 48.15 per cent of the votes, ahead of Trump (23.34 per cent), Rubio (16.67 per cent) and Kasich (10.66 per cent)

Cruz defeated Trump in Maine, securing 45.84 per cent of the votes during his second victory of the day. The billionaire followed with 32.55 per cent. Kasich was third with 12.17 per cent, and Rubio was fourth with eight per cent

The tycoon also won in Louisiana, with just a three per cent lead on Cruz. Trump had been leading for most of the night but Cruz caught up with him. Rubio was third with 11 per cent and Kasich followed at six per cent

Trump won Kentucky just four per cent ahead of Cruz. The tycoon had 36 per cent of votes while the Texas senator had 32 per cent. Rubio followed far behind at 16 per cent, followed by Kasich at 14 per cent

Donald Trump, pictured arriving for a press conference at his golf club in West Palm Beach, Florida, after the vote on Saturday, didn't do was well as expected in Louisiana and Kentucky, where he beat Cruz with only a short lead

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Trump had dominated the race in Louisiana for most of the night and was 10 per cent ahead of Cruz at times.

But his lead shrunk as time went on, and he won with 41 per cent of votes - not that far from Cruz's 38 per cent.

Trump's performance in Kentucky looked less certain as he was neck and neck with Cruz for most of the vote - even delaying his final speech until he heard the state's official results.

Both states were a bust for Rubio, who came out third with 16 per cent of votes in Kentucky and 11 per cent in Louisiana.

Trump said in his victory speech he was 'very happy' about his victories in Louisiana and Kentucky.

He made light of his losses in Kansas and Maine, calling them 'a strong second' and saying he hadn't spent much time campaigning there anyway.

Cruz crushed Trump in both states, emerging with a 13 per cent lead on the tycoon in Maine and 25 per cent in Kansas.

This came even though Maine governor Paul LePage endorsed Trump last month, saying the billionaire wanted to 'make America great again' and was 'the only one doing that right now'.

More than 18,600 Republican voters turned out to pick their nominee in Maine, the state's Republican Party chairman Richard Bennett said as he announced the results on Saturday night.

Rubio did poorly in Kansas, finishing with 17 per cent of the votes, but performed even worse in Maine, finishing last with only eight per cent.

A high turnout was seen in Kansas, with dozens of county locations exceeding 2012 voter turnout by four or five times, said Kansas GOP chairman Kelly Arnold.

'It’s been an amazing night. I've been in competitions all my life and there is nothing so exciting as this stuff,' Trump said during his victory speech in West Palm Beach, Florida.

'I want to congratulate Ted on Maine and Kansas. He should do well in Maine because it's really close to Canada, lets face it,' the tycoon quipped, alluding to Cruz's former Canadian citizenship, which he has renounced.

Trump then said Rubio had a 'very, very bad night' and called for him to drop out of the race.

'I'd love to take on Ted one on one. That would be so much fun. I want Ted one on one,' Trump said.

'The biggest story in all of politics isn’t what's happening tonight but the tremendous outpouring of voters coming to the Republican party,' he continued. 'Millions and millions of people are coming in and voting and they’ve never seen anything like this before.

'What's happening is a movement and I'm very honored to say that if I weren’t involved it wouldn’t be happening.

'I'm kidding. Not really but I'll say I'm kidding because I want them to say I'm a nice person'

Trump's speech also hit out at the establishment.

'The establishment is very unhappy with the way things are going - although I used to be part of the establishment. Seven months ago I was, but now I'm not.'

He then said the establishment wanted a candidate who needed money and thus could be 'controlled'.

'I'm self-funding, I'm not under control and I'm going to do what's right for the American people.'

Cruz, pictured talking to his supporters in Wichita, Kansas, said his victory in the state was a sign that Republican voters wanted to stand behind 'the strongest candidate' to ensure Trump doesn't end up as their nominee

Trump, pictured making his final speech in West Palm Beach, Florida, downplayed his losses in Kansas and Maine, saying he hadn't spent much time campaigning in both states

Although Kansas is an important win for Cruz, it does not provide any strong evidence of a Romney effect because the senator already has strong support in the Midwest.

'What we saw in Kansas is a manifestation of a real shift,' Cruz said while discussing his victory from Coeur d'Alene, Idaho. 'By any measure, Kansas and Maine and the CPAC are all very different groups of voters and to see strong wins across the board is very encouraging.

'What it represents is Republicans saying it would be a disgrace for Trump to be our nominee and we're going to stand behind the strongest candidate in the race.'

Cruz strongly hinted that other Republican contenders should drop out to let voters concentrate on him - and evict Trump.

'No other candidate has beaten him more than once. People recognize that if we're divided Donald wins, and if Donald wins, Hillary wins,' he said.

'There are good and honorable people in this race but now is the time for us to come together.

'As long as the field remains divided it gives Donald an advantage.There comes a point where other candidates need to reflect: "Do I have a path going forward or is it time for us to come together?" But it will be other candidates' decision to make that choice.'

Earlier in his victory speech, Cruz addressed a jubilant crowd: 'We have seen Republicans and Conservatives coming together, men and women who love freedom and the constitution, uniting and standing as one behind this campaign.

'Our constitutional rights are are under assault as America has receded from leadership in the world.

'And I am here today with a message of hope: All across the country people are waking up.'

Rubio did worse today than during his unsuccessful Super Tuesday, during which he only won one state, Minnesota.

He told reporters in Puerto Rico that he acknowledged his losses but remained hopeful. Delegates are awarded on a proportional basis, meaning he has secured a few more despite his scores.

'Many of the states that voted tonight are states that, quite frankly, some of my opponents just do better in, and I recognized that going in.

'But we wanted to make sure that we got our fair share of delegates in this proportional process. We're soon going to be in the winner-take-all process, in larger states like in Florida, and in other places like that, and that's where we feel very confident moving forward.'

The Texas senator, pictured Saturday in Coeur d'Alene, Idaho, said after his Kansas victory: 'As long as the field remains divided it gives Donald an advantage. There comes a point where other candidates need to reflect: "Do I have a path going forward or is it time for us to come together?"'

Trump, pictured at a rally in Orlando, Florida, on Saturday, took a jab at Cruz during his press conference in West Palm Beach, Florida, on Saturday night, saying the Texas senator was popular in Maine because it was close to Canada, Cruz's birthplace

Long lines: High turnout in Kansas has seen up to four times the numbers compared to the 2012 primaries. Pictured, voters queue at Olathe South High School

Strong support: Cruz shakes the hand of a Republican voter at a Kansas caucus, where he secured a win with half of the votes

Earlier in the day, Trump pushed his bid in Kansas. 'If I lose I'm going to be so angry at you!' he told the crowd at a rally in Wichita.

Addressing polls which show Hillary Clinton beating him in a national election, Trump cited - but did not name - other polls in which he claims he is winning.

He said: 'I'm already beating her [Clinton] and I haven't even got started yet!'

Taking to the stage in typically bombastic style, Trump lashed out at his usual targets including the media and the Republican establishment, as well as new-found foe Mitt Romney.

He said: 'The establishment is against us, the press is against us, but they are coming around.

'They keep saying "Trump can't win". I was not supposed to beat Jeb Bush. What happened to their candidate? It is so foolish.

'Republicans are eating their own right now, we have to bring things together, if we win.'

Even though polls suggested early on that Trump wasn't doing well, his Kansas supporters were out in force.

Connie Belton, 65, a retired homemaker from Wichita, Kansas, had a message for Republicans who are uneasy about the potential nomination of Donald Trump as she voted in Kansas on Saturday.

All smiles: A man dressed as Donald Trump's proposed Mexico wall was pictured at the Trump rally in Florida

Despite his flailing numbers, Trump's rally in Florida was met with a standing ovation

But at the University of Central Florida, protesters stood together against what they dubbed as Trump's campaign of hate

Meanwhile in Kansas, Trump reminded a rally of supporters this morning that he had snubbed the Conservative Political Action Conference to be with them, adding: 'If I lose I'm going to be so angry at you'

'If the big, fat GOP don't like him, they don't like me,' Belton said, adding that if he isn't the nominee she is going to write his name in on the ballot. She attended a rally Saturday before going to the caucus to vote for him.

'I adore Trump. I think his heart is as big as his hands,' she said. 'And as big as other things, as he says.'

Meanwhile in Kentucky, Tucker Oldham said he would throw his weight behind 'anybody but Trump.'

He decided on Marco Rubio, not because he particularly likes him but because he believes he has the best shot at rallying the Republican establishment and taking on the billionaire.

Oldham, 46, said he is horrified by Trump's vulgar talk and vague campaign promises, and believes he's nothing more than 'a marketing machine.'

Meanwhile Cruz also appeared on the stump in Kansas Saturday, appealing to working class voters 'with callouses on their hands' and repeating pledges to scrap Obamacare, abolish the IRS and introduce a flat-rate tax system.

Rubio, who lost ground to Cruz on Super Tuesday, addressed CPAC with a veiled swipe at Trump, saying conservatism is 'no about how long you can shout or how many names you can call people'.

In a pitch aimed at young voters, saying: 'The election of 2016 is no longer about a choice between ideologies or parties, the question is what kind of country is this going to be in the 21st century.

Cruz spoke to supporters in Wichita, appealing to working class voters 'with callouses on their hands' with plans to abolish the IRS and introduce a flat tax rate

Marco Rubio addressed young conservatives at CPAC, telling them they faced a critical time in the history of America and taking several veiled swipes at Trump

John Kasich appeared in front of supporters in Holland, Michigan ahead of his own must-win election in Ohio

'We, you, could be the first generation of Americans that inherit a worse country than the one that was left for our parents.'

Cruz touted the opportunities America provided his own parents, saying that the same opportunities would not be available if 'a Clinton or a Sanders is the next president'.

Then, to riotous applause, he said that the same opportunities would not be available 'if the party is hijacked by someone who is not a Republican' - another hit at Trump.

Rubio was expected to go to Florida after that rally to begin campaigning ahead of the must-win primary in his home state on March 15.

Cruz, who is wrestling with Rubio for the anti-Trump vote, has already put the pressure on that race, saying failure by Rubio to win would spell the end of his campaign. Cruz already secured his home state of Texas last week.

John Kasich also held a rally today in Traverse City, Michigan, laying out his plan for tax breaks on small businesses ahead of a his own must-win race in Ohio.

Trump's decision to skip an appearance Saturday at a conference sponsored by the American Conservative Union in the Washington area to get in one last Kansas rally rankled members of the group, who tweeted that it 'sends a clear message to conservatives.'

The billionaire businessman's rivals have been increasingly questioning his commitment to conservative policies, painting his promise to be flexible on issues as a giant red flag.

'Donald is telling us he will betray us on everything he's campaigned on,' Cruz told voters Friday in Maine.