Washington: Attempting to reassure anxious donors, Hillary Rodham Clinton outlined her plan for beating current Democratic presidential front-runner Barack Obama in a pair of primaries next month that even some of her supporters say she must win to stay in the race.

Clinton insisted that her campaign is on track and moving forward, despite losing 11 contests to Obama since February 5.

"I am very optimistic and extremely positive about what we're doing as we go forward in these states," Clinton said of Ohio and Texas, two delegate-rich states on which she has pinned the future of her candidacy.

"I hear with increasing frequency, 'Don't give up, you're going to win'," she said, speaking at a Boston fundraiser Sunday.

Ohio and Texas both hold primaries next week, with 334 delegates combined, and former President Bill Clinton has said publicly his wife probably needs to win both of them if she is to win the Democratic presidential nomination.

Narrowing lead

Recent polls show the race in Texas to be a statistical dead heat. In Ohio, polls show Clinton with a narrowing lead.

On the Republican side, John McCain's march toward clinching his party's nomination moved ahead Sunday as he swept all 38 nominating convention delegates awarded in US territories over the weekend.

Clinton on Sunday pledged to continue to stress her differences with Obama on issues including universal healthcare, and said she will step up her criticism of the Illinois senator's lack of experience in public life.

"We're going to emphasise more and more the experience gap," Clinton told several hundred supporters who had paid at least $500 (Dh1,836) to attend the Boston fundraiser.

"You'll hear a lot about it the next eight days."

In Ohio, Obama accused Clinton on Sunday of trying to walk away from a long record of support for the North American Free Trade Agreement, the free trade agreement with Mexico and Canada that he said has cost 50,000 jobs in Ohio.

At the same time, he said attempts to repeal the trade deal "would probably result in more job losses than job gains in the United States."