Bernie Sanders has won the West Virginia primary in the Democratic race for the presidential nomination, US media project.
The Vermont senator still trails Hillary Clinton in the overall contest for delegates but this win keeps his slim hopes alive.
“We are going to fight for every last vote,” he said in a victory speech that also attacked Republican Donald Trump.
Trump was declared the winner in West Virginia and in Nebraska.
But Trump faces a huge task in trying to get the Republican party behind him, as doubts persist about his substance and style.
House Speaker Paul Ryan, the party’s highest-ranking elected official, has said he is unable to endorse the New York businessman because he lacks conservative principles.
With Trump now the Republican presumptive nominee, it was the Democratic race that provided the focus for Tuesday’s primaries, reports the BBC.
Sanders’s victory in West Virginia, where Mrs Clinton convincingly beat Barack Obama in 2008, will prolong the Democratic contest.
In a speech delivered in Salem, Oregon, which holds its primary next week, Sanders vowed to fight on.
“We have now won primaries and caucuses in 19 states and let me be as clear as I can be – we are in this campaign to win the Democratic nomination.”
He pointed to polls as evidence that he remained the best Democratic candidate to beat Donald Trump.
And he turned his fire on the billionaire property developer for insulting women, Hispanics, Muslims, African Americans and veterans.
Despite his differences with the former secretary of state Mrs Clinton, Mr Sanders said, they had one common goal – defeating Trump.
Exit polls in West Virginia suggested one-third of those who voted for Sanders would switch to Trump in a general election between the two men.
