Mr McCain, an Arizona senator, defeated former Massachusetts Governor Mitt Romney in a tight Florida battle that gives him critical momentum heading into critical Feb 5 'Super Tuesday' voting in 21 states with Republican contests.

With about three-quarters of the vote counted, Mr McCain led Mr Romney by 36 per cent to 31 per cent.

'Our victory might not have reached landslide proportions, but it is sweet nonetheless,' Mr McCain told supporters chanting 'Mac is back' in Miami.

'In one week we will have as close to a national primary as we have ever had in this country. I intend to win it, and be the nominee of our party,' Mr McCain said. 'We have a ways to go, but we're getting close.' Mr Giuliani, a former New York mayor who staked his campaign on a strong showing in Florida, was leading former Arkansas Governor Mike Huckabee for a distant third-place finish after being ahead in national polls for much of the past year.

Mr Giuliani planned to drop out and endorse Mr McCain, a friend and political ally before the presidential race began, on Wednesday, according to media reports.

Mr McCain thanked Mr Giuliani 'for all you have added to this race,' and Mr Giuliani talked about his campaign in the past tense during a speech to supporters in Orlando, Florida.

'We ran a campaign that was uplifting,' Mr Giuliani said. 'You don't always win, but you can always try to do it right.'

Front of the pack
Mr McCain's win puts him at the front of the pack in a seesawing Republican race to pick the party's candidate in November's presidential election. He picks up all of Florida's 57 delegates to the national nominating convention.

New York Senator Hillary Clinton easily won a Florida Democratic race that featured no active campaigning because of a dispute between the national and state parties.

The national party stripped the state of its delegates to the national convention and Democratic candidates pledged to stay away.

Mrs Clinton, who lost to rival Barack Obama in a landslide in South Carolina on Saturday, visited Florida after polls closed in a bid to claim at least a symbolic victory.

'Thank you Florida. I could not come here to ask in person for your votes but I am here to thank you for your votes,' she told supporters in Davie, outside Fort Lauderdale.

Exit polls showed the economy was the top issue among Republican voters in Florida, with about half listing it as their most important topic. About six in 10 voters described themselves as conservatives.

Mr McCain and Mr Romney had dominated the headlines in Florida with a heated battle over who was best prepared to rescue a struggling economy and lead a country at war in Iraq and Afghanistan.

Mr McCain had gained in polls in recent days after endorsements by Florida Governor Charlie Crist and US Senator Mel Martinez of Florida.

Mr McCain and Mr Romney split the last four of the state-by-state nominating contests. Mr McCain won in South Carolina and New Hampshire and Mr Romney carried Michigan and Nevada, the latter a state scarcely contested by other Republicans. Mr Huckabee won the kick-off contest in Iowa.

Mr Romney aides said the result made the Republican race for the nomination a two-man battle between Mr Romney and Mr McCain and he would press ahead to Feb 5.

'I think it's time for the politicians to leave Washington and for the citizens to take over,' Mr Romney, a wealthy venture capitalist who has touted his real-world business experience, told supporters in St Petersburg, Florida.

'At a time like this, America needs a president in the White House who has actually had a job in the real economy,' he said.

Mr Huckabee also said he planned to go on to compete in the Feb 5 contests, which include several Southern states like his home state of Arkansas, and Alabama, Oklahoma, Tennessee and Georgia.

'We're a long way from quittin',' he said on Fox News Channel. -- REUTERS