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"We will be celebrating for a long time tonight".

With about 90 per cent of the votes counted, U.S. med-ia gave Trump about 46 per cent, with senators Marco Rubio and Ted Cruz trailing by more than 20 points in a tight race for second.

"We're winning, winning, winning the country", Trump said Tuesday at a caucus night celebration in the Treasure Island casino on the Las Vegas Strip.

"We won the evangelicals...We won with young, won with old". "Now we are winning winning, winning the country", Trump said, claiming victory to a crowded hall.

Trump's decisive win is likely to further frustrate Republican establishment figures who, less than a month ago, were hoping that the insurgent candidacy of the outspoken businessman was stalled after he lost the opening nominating contest in Iowa to Cruz. "We won with poorly educated", he said.

As in the past three contests, the billionaire real estate mogul performed best among Republican voters who were looking for a candidate who "tells it like it is", receiving 86 percent of their support.

Mr Rubio, already campaigning in MI as Nevada results rolled in, was projecting confidence that he can consolidate the non-Trump voters, saying "we have incredible room to grow".

"We're gonna get greedy for the United States", he pledged.

This poses a challenge for Cruz and Rubio who have been playing catch-up with Trump since his big wins in SC and New Hampshire.

"One week from today will be the most important night of this campaign", Cruz said after his finish. Polls show the former first lady with a huge advantage among African-Americans, which bodes well for her prospects in the southern states that vote on Super Tuesday.

Trump said he was happy he was the top vote-getter among Hispanic voters in the caucus. Currently, Trump has 67 delegates and Cruz and Rubio are following with 11 and 10 delegates, respectively.

It is also the first test of Republican voter sentiment after Jeb Bush pulled out of the race last week following a poor showing in SC.

Donald Trump might tone down his abrasive approach if he wins the Republican nomination, he said hours after winning the Nevada caucuses, but for now he believes it works well for him.