Washington  - Hillary Clinton will be looking to prolong the race for the Democratic nomination with contests in Kentucky and Oregon on Tuesday even though her chances of narrowing rival Barack Obama's lead remain slim.

Polls show that Clinton, 60, should easily win in Kentucky but that she trails Obama, 46, in Oregon. But even if she pulls out wins in both states, Clinton is unlikely to make much of a dent in Obama's overall lead in the delegate count.

Clinton is about 200 delegates behind Obama in the state-by-state contests called primaries, with 103 delegates up for grabs in Tuesday's vote. After Tuesday, only three more primaries remain until June 3.

A strong showing by Obama Tuesday would mean he could capture a majority of all delegates for the Democratic nomination, but would still fall short of the 2,025 needed to seal his candidacy for the November 4 presidential election.

"We will have a majority of the pledge delegates," Obama said on ABC television Tuesday. "Obviously we won't have completed the nomination process, but I think it's an important milestone for our campaign."

Clinton has vowed to fight on until all votes have been counted, pledging to stay in the race at least until June 3, when Montana and South Dakota cast the final ballots of the campaign.

Clinton hopes that strong showings in the final leg of the race will persuade the undecided super-delegates, a group of party elite which votes independently of the states will tilt the nomination in her favour.

Clinton has faced increasing pressure to drop out of the race so the Democrats have time to unite against the presumptive Republican nominee John McCain. Many party insiders worry the bitter campaign will leave the party weakened ahead of the presidential election.

The Democrats have already begun to take steps, as the Clinton and Obama camps have started discussing how to merge fundraising forces once the nominee has been determined. The party has also won the backing of both candidates to begin raising money for whomever wins the race.

Obama, assuming he will win the nomination, has started campaigning in states whose primaries have already taken place but will be crucial in the general election. Obama planned on campaigning in Florida later this week.

Clinton handily won the January 29 vote in Florida, but the delegates do not count because the state moved up its primary in violation of party rules. Clinton has since fought to force the party to allow the Florida delegates to be seated at the convention.

The formal Democratic nomination convention is in late August in Denver, Colorado, followed by general elections on November 4. (dpa)