Republican Donald Trump and Democrat Bernie Sanders have shaken up the US presidential race with decisive victories in the New Hampshire primary.
Democrat Bernie Sanders, left, and Republican Donald Trump Photo: AFP/FILE
Billionaire Mr Trump is likely to get more than twice the number of votes of the next Republican candidate.
Senator Sanders, who beat Democratic rival Hillary Clinton by a huge margin, said his victory showed people wanted "real change".
Both candidates are riding on a wave of discontent with mainstream politics.
Ohio Governor John Kasich came second in the Republican vote, with former Florida Governor Jeb Bush, Texas Senator Ted Cruz and Florida Senator Marco Rubio all vying for third place.
New Hampshire is the second state to choose delegates in the long nomination battle following last week's Iowa caucuses, which were won by Mr Cruz for the Republicans and Mrs Clinton for the Democrats.
The result gives momentum to the winners ahead of the next contests in South Carolina and Nevada.
Mr Trump's lead in New Hampshire is the first time the New York businessman - who has never held elected office - has translated his widespread support in opinion polls into a victory at the polls.
In his victory speech, the real estate mogul congratulated Mr Sanders but sideswiped that "he wants to give away our country, folks!"
Mr Trump, 69, has pledged to deport millions of migrants who are living in the US illegally; build a wall along the border with Mexico; and impose a temporary ban on all Muslims entering the country.
With close to 90 percent of the votes counted, Mr Sanders has a lead of more than 20 percentage points over Mrs Clinton in the two-horse race for the Democratic nomination.
He had topped polls in New Hampshire in recent months, but it is still a significant victory for the self-described Democratic socialist candidate.
"What the people here have said is that given the enormous crises facing our country, it is just too late for the same old, same old establishment politics and establishment economics," Mr Sanders said in speech to his supporters late on Tuesday.
The 74-year-old has vowed to eradicate income inequality, provide free university education and break up big banks.
Mrs Clinton congratulated Mr Sanders, but said in a speech she would continue to fight for every vote in the campaign. Despite the setback, she still remains the frontrunner for the nomination.
Her campaign manager, Robby Mook, said in a memo that they expected the race for the Democratic nomination "very likely" to be decided in March.
The former secretary of state acknowledged before the polls that Mr Sanders had a natural advantage in New Hampshire because he represents the neighbouring state of Vermont as senator.
Mrs Clinton, who has more support from the Democratic establishment, narrowly won in Iowa.
Most polls in New Hampshire closed at 7pm local time (1pm NZT), with state officials forecasting a historic turnout in the vote.
- BBC