Progressive firebrand Bernie Sanders earned a decisive victory Saturday in the Nevada caucuses, solidifying his frontrunner status in the race to choose the Democratic nominee who faces President Donald Trump in November's election.

His win is a substantial accomplishment in a state seen as an important bellwether because it is the first diverse electorate to weigh in on the 2020 presidential race.

It also shows that Sanders has been able to broaden a coalition beyond the narrow limits of leftist voters, refuting the argument used by several moderates in the race that he would not be able to bridge the divide between progressives and centrists.

By late Saturday with official results slowly trickling in, Sanders was comfortably ahead with some 22 percent of precincts reporting.

The 78-year-old senator from Vermont was leading with about 46 percent, followed by former vice president Joe Biden at 23 percent.

South Bend, Indiana's former mayor Pete Buttigieg, who scored a shock narrow win in Iowa to start the race nearly three weeks ago, stood at a distant third a 13 percent.

The two female US senators in the running, progressive Elizabeth Warren and pragmatist Amy Klobuchar, were well back, in single digits. 

Sanders was quick to claim victory, saying his "multi-generational, multi-racial coalition" that won Nevada is "going to sweep this country."

His progressive policies, including universal health care, higher taxes on the wealthy and corporations, and raising the minimum wage have struck a chord with millions of Americans.

"The American people are sick and tired of a government which is based on greed, corruption, and lies. They want an administration which is based on the principles of justice," he told a raucous rally, which responded with chants of "Bernie! Bernie! Bernie!"

Sanders was speaking in El Paso, Texas, one of the 14 states that votes on "Super Tuesday" on March 3. 

Buttigieg congratulated Sanders on his Nevada victory. But the moderate, 38-year-old military veteran offered a stern warning against picking a self-described democratic socialist who sees "capitalism as the root of all evil" to go up against the populist Trump.

"Senator Sanders believes in an inflexible, ideological revolution that leaves out most Democrats, not to mention most Americans," Buttigieg said in remarks that took on a surprisingly coarse tone.

With Sanders coming in virtually tied for first in Iowa and then winning New Hampshire last week, he is in the driver's seat against his seven rivals as the race turns toward South Carolina and then Super Tuesday.

"Looks like Crazy Bernie is doing well in the Great State of Nevada," Trump tweeted, maligning other candidates before adding: "Congratulations Bernie, & don't let them take it away from you!"

With the race soon taking on a national dynamic, several candidates like Klobuchar, Warren or congresswoman Tulsi Gabbard will be under pressure to decide whether they fight on or throw in the towel. 

- 'Coming back' -

The centrist Biden, desperate to right a listing ship after miserable showings in the first two states, told supporters he feels "really good" about his Nevada finish and shouldn't be counted out.

"We're alive and we're coming back," the onetime frontrunner insisted. "We're going on to South Carolina to win and then we're going to take this back!"

South Carolina has a majority black Democratic electorate, and Biden leads polling there, riding his popularity among African Americans due in part to his eight years as popular president Barack Obama's deputy.

Sanders leads national polls with an average of 28 percent support.

That is 11 points ahead of Biden and 13 points clear of billionaire media tycoon Michael Bloomberg, the former mayor of New York who skipped campaigning in the four early states, including Nevada, in order to focus on Super Tuesday.

Sanders has been largely unchecked by opponents who have focused more on blunting the advance of Bloomberg, who has poured a staggering $438 million of his personal fortune, an all-time record, into campaign advertising.

Warren, speaking late Saturday at a large rally in Washington state which votes on March 10, pledged to stay in the fight despite a third straight mediocre showing.

She repeated her attacks on Bloomberg, accusing him of seeking to "buy this election."

In Las Vegas, caucuses were held in several of the city's world-famous casinos and hotels, as well as dusty desert towns.

Keen to avoid the drawn-out embarrassment of the Iowa caucus, which relied on flawed technology to relay results, Nevada officials pivoted to a low-tech system that involved phoning in results to hotlines and backing them up with photographs of the tabulations.

The process was considerably slower than four years ago, but appeared to be relatively smooth.