WASHINGTON/NEW YORK - US Democratic presidential candidate Bernie Sanders defeated Hillary Clinton on Tuesday in West Virginia's primary, winning over voters deeply skeptical about the economy and signaling the difficulty Clinton may have in industrial states in the general election.

The loss slows Clinton's march to the nomination, but she is still heavily favored to become the Democratic candidate in the Nov 8 election.

In a November match-up with Donald Trump, Clinton will need to win over working-class voters in the US Rust Belt, which includes key states such as Ohio and Pennsylvania.

Trump, 69, won contests in West Virginia and Nebraska handily on Tuesday. The presumptive Republican nominee is set to meet with party leaders in the US Congress on Thursday, including US House of Representatives Speaker Paul Ryan.

After Ryan said last week that he was not yet ready to endorse Trump, Trump said on Sunday that he would have to decide whether he still wanted Ryan to preside over the party's July convention.

Trump said in a Fox interview on Tuesday night that he would like Ryan to chair the convention as planned. "He's a very good man, he wants what's good for the party," the New York billionaire said.

Trump has zeroed in on Clinton's protracted battle with Sanders, a 74-year-old US senator from Vermont. He has taunted Clinton in recent days by saying she "can't close the deal" by beating Sanders, her only rival for the Democratic Party's nomination since Feb 1.

Clinton, 68, has said she will ignore Trump's personal insults, including his repeated use of his new nickname for her, "Crooked Hillary," and instead will criticize his policy pronouncements.