Sen. Bernie Sanders will win the Nevada caucuses, Fox News projected Saturday, furthering the democratic socialist's lead over his Democratic rivals and raising the question of whether he can be stopped on his path to the Democratic nomination.

As returns came in, former Vice President Joe Biden was holding on to a second-place finish. Ultimately 36 delegates are at stake.

BIDEN VOWS RESURGENCE AFTER SANDERS' WIN IN NEVADA: 'I'M GOING TO TAKE THIS BACK'

"We just won the Nevada caucus. This grassroots movement is unstoppable," Sanders tweeted. "Together, let's win the Democratic nomination, defeat Trump and transform the country!"

Speaking to supporters in San Antonio, Texas, where he is campaigning ahead of the Super Tuesday contests, he boasted of putting "together a multigenerational, multiracial coalition" and said "it's going to sweep this country."

President Trump responded to the results by congratulating "Crazy Bernie" and by taking a shot at the rest of the field.

"Looks like Crazy Bernie is doing well in the Great State of Nevada. Biden & the rest look weak, & no way Mini Mike [Bloomberg] can restart his campaign after the worst debate performance in the history of Presidential Debates," he tweeted. "Congratulations Bernie, & don’t let them take it away from you!"

Sanders had been predicted to win the state comfortably. A Biden second-place finish is significantly stronger than the disappointing fourth- and fifth-place finishes in the first two states of Iowa and New Hampshire, and keeps alive his campaign's narrative that he is the best pick to occupy the centrist lane to beat Sanders and eventually Trump. But, depending on the size of Sanders' eventual victory, may raise questions about whether Biden can catch Sanders, and whether centrists should rally around a different candidate.

Speaking to supporters as results came in, Biden said he felt good about the state of his campaign, even after failing to win any of the first three states.

"We're alive and we’re coming back and we’re going to win," he said. "We're going to win in South Carolina, and then Super Tuesday and we are on our way."

The caucuses mark a pivotal moment as candidates sought to prove that they can attract support for a more diverse electorate in the state -- where there is a significantly higher Latino population than in Iowa and New Hampshire. Nevada’s population, which is closer to that of the country as a whole than the more white Iowa and New Hampshire, is 29 percent Latino, 10 percent black and 9 percent Asian American and Pacific Islander.

Biden has seen competition for that moderate mantle from others including former South Bend, Ind. Mayor Pete Buttigieg, Sen. Amy Klobuchar, D-Minn., and also billionaire Mike Bloomberg -- who is not on the ballot in the caucuses, but is creeping up the polls nationally.

TRUMP CONGRATULATES SANDERS ON NEVADA CAUCUSES: 'DON'T LET THEM TAKE IT AWAY FROM YOU'

Klobuchar, in a speech to supporters in her home state of Minnesota, tried to put a spin on what looked likely to be a sixth-place finish in Nevada.

"They’re counting the votes but as usual I think we have exceeded expectations,” she said, before adding that “a lot of people didn’t think I’d be standing at this point.”

Buttigieg meanwhile used his speech to take a shot at Sanders, warning against a "rush" to nominate the radical candidate and accusing him of calling for an "inflexible, ideological revolution that leaves out most Americans."

Buttigieg's comments represent a growing fear from more moderate Democrats that, with a tie in Iowa and a win in New Hamshire and now Nevada, that Sanders could soon be out of sight -- something that moderate Democrats fear could hand Trump re-election.

The closely-watched caucus process began Saturday with Nevada Democrats optimistic that they would avoid a repeat of the technical glitches that plagued the caucuses in Iowa. Those fears led the state Democratic Party to decide to rely on traditional reporting by phone, rather than an app made by the same developer that created the app blamed for the debacle in Iowa. It has also scrapped a plan to use a Google Forms app loaded onto iPads.

For the first time, Nevada held early voting, from last Saturday through Tuesday. Roughly 75,000 people cast ballots, which was nearly as many people who took part in the state's entire 2016 Democratic caucuses. But since this is a caucus, the ballot was far from simple. Voters were given ballots to rank their choice of candidates. The early-voting ballots were then married with those of caucus-goers on Saturday – in both the first round and the realignment.

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Shortly after the caucuses got underway, the state Democratic Party pushed back against early reports of party volunteers not showing up to administer caucuses at a number of sites, meaning they were being replaced by campaign precinct captains as site leads or site chairs. Sources in one campaign said the developments were "huge red flags" and that a number of sites do not have their early voter data needed to calculate the first alignment.

"To correct the record, there is no volunteer shortage in NV. We have an average of eight volunteers per caucus site, so roughly 2000+ across the state. Also, it's common for campaign volunteers to help with running precincts on Caucus Day," Nevada Democratic Party spokesperson Molly Forgey said. "This happened here in both 2016 and 2008."

Candidates now gear up for the primary in South Carolina next Saturday, before the vital Super Tuesday primaries on March 3.

Fox News' Jacqui Heinrich, Lee Ross and The Associated Press contributed to this report.