Vermont Senator Bernie Sanders is set to win the Democratic caucus in the US state of Hawaii by a wide margin against former secretary of state Hillary Clinton, media reports said Sunday.
Sanders is reported to have already won the Democratic caucuses in Alaska and the north-western US state of Washington by substantial margins Saturday.
The Washington state Democratic Party announced that Sanders led Clinton by 72.9 per cent to 27.1 per cent.
In Alaska, Sanders won 80 per cent of the ballots, while Clinton stood at 20 per cent, according to CNN.
The Democratic Party of Hawaii has reported that it is still counting results, but US media is reporting a similar margin of victory for Sanders over Clinton as in the two other states.
Sanders, a longtime member of the US Congress and self-declared democratic socialist, has proven an unexpectedly strong challenger but Clinton continues to be favoured to secure the nomination through the state-by-state nominating process ahead of July party conventions.
The candidates have devoted relatively little attention to remote Alaska and Hawaii, states with relatively small populations that are located far from the rest of the United States.
Clinton leads the race to secure the most delegates to the party convention that are awarded through the state primary and caucus votes, with some 1,690 to Sanders' 946, according to a New York Times tally ahead of Saturday's vote.
On the Republican side, Donald Trump leads, but the party establishment has yet to back his candidacy and opponents hope to force an alternate candidate to get the nod in a disputed convention.