Bernie Sanders has swept to victory over Hillary Clinton in all three states that voted for the Democratic presidential nominee on Saturday.

The biggest prize was Washington state, but Mr Sanders also won in Alaska and Hawaii, boosting his campaign.

He was estimated to have taken more than 70% of the vote in all three.

Mr Sanders thanked his supporters and said his “campaign has the momentum”, but he still faces a tough task to overhaul Mrs Clinton.

She went into Saturday’s votes leading Mr Sanders by 1,223 delegates to 920.

When superdelegates – party officials who can support either candidate – who have so far declared their allegiance are included, Mrs Clinton was ahead by 1,692 to 949 in the race to reach 2,383 delegates.

Washington was the most significant of the three states voting on Saturday, with 101 delegates up for grabs. There were 16 delegates on offer in Alaska and 25 in Hawaii.

Mr Sanders was projected to have won 72% of the vote in Washington against 27% for Mrs Clinton.

US TV networks gave him about 79% of the vote in Alaska, against 21% for Mrs Clinton. In the Hawaii caucus Mr Sanders won by 71% to 29%.

Celebrating via Twitter, Mr Sanders said: “Thank you, Alaska! Together we are sending a message that this government belongs to all of us... Washington, thank you for your huge support! It is hard for anybody to deny that our campaign has the momentum.”

Mr Sanders earlier told supporters in Wisconsin: “This is what momentum is about. Don't let anybody tell you we can’t win the nomination or win the general election. We’re going to do both of those things.”

Mr Sanders had spent the week on the west coast, rallying support among liberals and the left-wing.

Mr Sanders was trying to build on overwhelming victories in last Tuesday’s caucuses in Idaho and Utah.

However, he suffered defeat in Arizona, and although his delegate haul from the three states was 20 higher than Mrs Clinton, he failed to make major inroads into her lead.

Mrs Clinton has pointed out that she has “2.6 million more votes” than Mr Sanders.

She campaigned less in the three states that voted on Saturday, perhaps expecting the defeats, and spent Easter with her family.

Despite Saturday’s results, the battle will be won and lost in far bigger states still to come. In RealClearPolitics poll averages, Mrs Clinton has the lead over Mr Sanders by nine percentage points in California, 34 points in New York and 28 in Pennsylvania.

Calculations suggest Mr Sanders may need to win two-thirds of the remaining delegates – in primaries, caucuses and among so-far uncommitted super-delegates – the unelected officials who can vote for their candidate of choice at the party’s election convention.

•Excerpted from a BBC report. Photo shows US Democratic hopeful Bernie Sanders.

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