The US’ progressive firebrand Bernie Sanders earned a decisive victory on 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 on Saturday, Sanders was comfortably ahead with half of all precincts reporting.

The 78-year-old senator from Vermont was leading with about 46 per cent, followed by former vice-president Joe Biden at 19 per cent.

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 in third at 15 per cent.

The two female US senators in the running, progressive Elizabeth Warren and pragmatist Amy Klobuchar, were on 10 and four per cent respectively.

Sanders was quick to claim victory, saying his “multi-generational, multi-racial coalition” that won Nevada was “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 vote 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 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.

With Sanders coming in virtually tied for first in Iowa and then winning New Hampshire last week, he is in the driver’s seat 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.