Hillary Clinton has cruised to a crushing win over Barack Obama in West Virginia's primary, but did little to shake her rival's stranglehold on the Democratic White House race.

Television network projections handed victory to the former first lady as soon as the polls closed, highlighting African-American Obama's struggle to win over white, working class voters who play a key role in general election swing states.

"You will never quit, and I won't either," Clinton told cheering supporters at her victory rally on Tuesday.

"There are some who have wanted to cut this race short," Clinton said.

"I am more determined than ever to carry on with this campaign until everyone has had their chance to make their voices heard," Clinton said, in a hint she may carry on through the five remaining nominating contests.

With 20 percent of the votes in, Clinton led Obama by 63 percent to 30 percent in the 95 percent white state, which has only 28 of the 2025 pledged delegates needed for the nomination.

But the win was not sufficient to upset the mathematical equation in the race, which Obama leads by every metric — pledged delegates, party insiders or superdelegates, the popular vote and nominating contests won.

Obama had already conceded the primary and was in the general-election battleground of Missouri as results came in, as he geared up for a potential November face-off against Republican John McCain.

But the former first lady argued she was the best bet to win white swing voters in crucial battleground states like Pennsylvania and Ohio, in a general election showdown against McCain.

"I am in this race because I believe I am the strongest candidate," she said.

The former first lady fired off a fundraising appeal within an hour of polls closing, underscoring her indebted campaign's desperate need for cash to carry on.

Exit polls cited by MSNBC showed that Clinton won white voters by 68 percent to 28 for Obama, and won 72 percent of those earning less than $50 000, compared to her foe's 24 percent.

Early exit polls cited by CNN said that 64 percent of voters in West Virginia said the economy was the number one issue, with Iraq second on 19 percent.

Worryingly for Obama, who is vying to become America's first black president, Fox News exit data said 51 percent of voters believed that he shared the views of his controversial former pastor Jeremiah Wright, who sparked a crisis for his campaign with racially tinged sermons.

Earlier, Clinton's odds grew longer still as Obama racked up more party insiders, or superdelegates, including Roy Romer, a former governor of Colorado.

Romer, an ex-chairperson of the Democratic National Committee who was a national co-chairperson of president Bill Clinton's re-election campaign in 1996, said "Senator Clinton has been a very strong and formidable candidate.

"But there is a time that we need to end it and direct ourselves to the general election. I think that time is now," he said on a media conference call.

The two senators had a close encounter earlier on Tuesday as they made a rare appearance in Congress for a series of votes.

As she walked into the Capitol building, Clinton was asked how she felt about West Virginia and replied "excellent."

At one point, Obama approached Clinton and patted her on the shoulder and the arm, and she smiled broadly as they exchanged a few words before he left the Senate chamber.

As he awaited his expected defeat, Obama made the point that he is the all but inevitable Democratic nominee, looking ahead to a matchup with McCain, heading to midwestern Missouri.

"While the Bush-Cheney ticket won't be up for re-election, the Bush-Cheney policies will, because John McCain is running for four more years of the same approach that has failed the American people," Obama said in Cape Girardeau, referring to President George W. Bush and Vice President Dick Cheney.

"His only answer to the problems created by George Bush's policies is to give them another four years to fail. Just look at where he stands and you'll see that a vote for John McCain is a vote for George Bush's third term."

Before West Virginia's votes were counted Obama's tally of superdelegates on the RealClearPolitics website rose to 283, against 272 for Clinton. In total, including delegates elected in state contests, he has 1874 to her 1698, nearer the winning line of 2025.

AFP