Hat-trick for Sanders as he wins caucuses in Hawaii

Bernie Sanders has won the Democratic presidential caucuses in Hawaii, his third win over front-runner Hillary Clinton in the three states that held party caucuses on Saturday.

The Vermont senator also won caucuses in Washington state and Alaska.

The Saturday sweep gives a powerful psychological boost to Sanders' supporters.

But the results are barely denting Clinton's significant delegate lead in the race for the nomination.

Sanders has said he expects to close the delegate gap with Clinton as the contest moves to liberal north-eastern states.