Republican presidential candidate Donald Trump has easily won the US state of Nevada, cementing his lead in the race for the party’s nomination.
The billionaire now has three caucus wins in a row, after victories in New Hampshire and South Carolina.
Senators Marco Rubio and Ted Cruz, who have been trading barbs this week, came second and third respectively.
Party officials said they were checking reports of double voting and insufficient ballots at one site.
Some volunteers also wore clothing in support of Mr Trump, but officials said this was not against the rules.
In his victory speech, Mr Trump told a roaring crowd: “We’re winning, winning, winning the country, and soon the country is going to start winning, winning, winning.”
He also celebrated getting the support of the “poorly educated” and Latinos. Some 45% of Nevada’s Republican voters of Latino origin backed Mr Trump, according to entrance polls.
Nevada, typically a swing state with a substantial Latino population, is crucial to the election process. Hillary Clinton won the state on Saturday in the Democratic race.
With all votes counted, Donald Trump had 46% of the vote with his closest rival Marco Rubio getting 23%.
Mr Rubio defended his second-place finish, calling it an “unusual year” and an “unusual process”.
“The vast, overwhelming majority of Republicans do not want Donald Trump to be our nominee. As long as there are four people running, dividing up the non-Trump vote, you’re going to get results like what you saw last night… so the sooner we can get this race narrowed down, I think the easier it’s going to be to stop Donald Trump and defeat him.”
In the US primary elections, candidates win delegates who pledge to endorse them at the party conventions in July.
Thirty delegates – about 1% of the total – were up for grabs in the Nevada caucuses, the first Republican test in the western US. Donald Trump won 14 delegates; Marco Rubio seven and Ted Cruz six. John Kasich and Ben Carson each got one delegate, with one more still to be allocated.
To win the Republican nomination for president a candidate needs 1,237 delegates. So far, Mr Trump has 81 delegates and Mr Rubio and Mr Cruz have 17 each.
Cheers erupted at the Trump camp in Las Vegas as US networks started projecting his victory.