Audio: Gerard Baker on how Philadelphia changes the race | Analysis: Groundhog Day | How the night unfolded | 'A surreal face-off' | Video: Clinton's speech | Video: Obama's speech | Graphic: the battle for Pennsylvania | How Clinton can win it

Hillary Clinton declared "the tide is turning" after defeating Barack Obama in the Pennsylvania primary - the last big prize left in their epic struggle for the Democratic nomination.

With 99 per cent of the votes counted, she beat Mr Obama by ten per cent, a similar margin to the one she achieved last month in the equally pivotal state of Ohio.

Pundits had earlier said she needed a decisive double-digit margin to silence calls for her to pull out of a race which many exhausted Democrats fear is damaging their chances of re-taking the White House in November.

Mrs Clinton's victory means she lives to fight another day. "Some people counted me out and said to drop out," she told wildly cheering supporters, "but the American people don't quit - and they deserve a president who doesn't quit, either."

Both campaigns tried hard to lower expectations ahead of the vote, with Mr Obama saying he was always going to struggle in a state where Mrs Clinton's strength among white, working class voters made him the "underdog".

He left Pennsylvania before the polls closed, travelling instead to Indiana, where he believes the primary in a fortnight's time could turn out to be the "tie-breaker".

Speaking in Evansville he hinted at the bitterness of a six week battle in Pennsylvania in which she had suggested he was elitist and out-of-touch with ordinary voters.

"You cannot be the champion of working Americans if you are funded by lobbyists who drown out their voices," said Mr Obama, who has made much of Mrs Clinton's links to such groups. Her campaign has responded by saying their rival has not always been as pure in this respect as he claims.

Mr Obama then reprised his criticism of Mrs Clinton as a candidate who will say and do anything to win, saying that Democrats had the chance not only to re-claim an office "but the trust of the American people".

But he also said it was easy to forget what the campaign is supposed to be about by getting caught up in "the tit-for-tat" and silliness of politics, adding: "None of us are completely immune."

His aides say Mrs Clinton's gains in Pennsylvania could be wiped out in the elections on May 6 when North Carolina, a strong state for Mr Obama, is also holding its primary. Senior Obama advisers, David Axelrod and Robert Gibbs, were seen sporting T-shirts proclaiming: "Stop the drama, vote Obama."

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