Marco Rubio also picked up endorsements from several Nevada party leaders, including US Senator Dean Heller and Nevada Lieutenant Governor Mark Hutchison.
Republican presidential candidate Marco Rubio aimed to outpoll rival Ted Cruz in Nevada's caucus on Tuesday to bolster his position as the establishment favorite for his party's nomination for the November 8 election.
Looming over the tight race between the two first-term Cuban-American US senators is Republican front-runner Donald Trump, the billionaire businessman who has won two of the first three state nominating contests and is expected to dominate the field in Nevada.
With Trump, a blunt-spoken political outsider, commanding a double-digit lead in a handful of Nevada opinion polls, political strategists in the state said Rubio and Cruz had the more modest goal: a clear win over the other, which could propel them through the busy voting month of March.
"They're playing for second," said Nevada political analyst Jon Ralston.
A recent CNN/ORC poll put Trump ahead by 26 percentage points in Nevada at 45 per cent, followed by Rubio, from Florida, at 19 per cent and Cruz, from Texas, at 17 per cent.
Lagging behind were retired neurosurgeon Ben Carson, with 7 percent, and Ohio Governor John Kasich at 5 per cent.
Kasich, who finished second to Trump in the February 9 New Hampshire primary, kept his focus on bigger states, including Michigan and Virginia.
The rivalry between Rubio and Cruz, who won the first-in-the-nation Iowa caucuses on February 1, has intensified as both seek a boost going into the nominating contests in a dozen states on March 1, known as Super Tuesday.
On Saturday, Rubio beat Cruz by fewer than 1,000 votes for second place in South Carolina's Republican primary. Strategists said Rubio also benefited from the withdrawal from the race of one-time establishment favorite Jeb Bush, some of whose donors were preparing to shift to Rubio.
TRUMP BLASTS CRUZRubio also picked up endorsements from several Nevada party leaders, including US Senator Dean Heller and Nevada Lieutenant Governor Mark Hutchison.
His campaign staff was due to be joined by Marc Short, a senior political adviser to the billionaire industrialist brothers Charles and David Koch, Politico reported on Tuesday. Though they have not endorsed any candidates, the influential brothers spend tens of millions to advance their libertarian brand of politics, which would sharply limit the role of government.
The Cruz campaign, meanwhile, lost a key staffer on Monday when the candidate fired his main spokesman for posting a video that falsely showed Rubio dismissing the Bible.
Trump, who has made a habit of coming up with insults for his rivals that are unusually frank for a presidential candidate, appeared to be focusing his ire on Cruz.
Cruz "lies like a dog," Trump wrote on his Twitter account on Tuesday, adding in a separate message that Cruz also fired his spokesman "like a dog".
"Ted panicked," Trump wrote.
Rubio, a former casino workers' son who spent six years in Nevada as an adolescent, is playing up his ties to the region.
"He's not pushing it hard, like, 'I'm really a Nevadan,'" said Eric Herzik, a political science professor at the University of Nevada-Reno. "But both he and his surrogates have highlighted he has the best understanding of Nevada because he actually lived here."
Ralston estimated only 8 per cent to 10 per cent of eligible voters may turn up to caucus on Tuesday - or somewhere between 33,000 and 42,000 people, according to data from the Nevada secretary of state on registered Republican voters.
© Thomson Reuters 2016