Hillary Clinton won the Democratic primary in Pennsylvania Tuesday night, boosting her campaign against opponent Barack Obama.

A supporter of Democratic presidential hopeful Hillary Clinton makes the V-sign as Clinton is declared winner of the Pennsylvania primary.
(Carolyn Kaster/Associated Press)

"The tide is turning," she told cheering supporters after she was declared the winner.

With about 95 per cent of the vote counted, Clinton was leading Obama 55 per cent to 45 per cent.

As former president and husband Bill Clinton stood behind her, Clinton told supporters she was ready for the White House, saying she would address everything from cancer to the economy.

"I'm in this race to fight for you," she said, as the crowd chanted "Hil-la-ry."

Clinton was ahead in the areas where she had been expected to do well, among blue-collar and rural voters.

Obama, meanwhile, was leading in Philadelphia and its suburbs. But earlier Tuesday, he had conceded defeat in Pennsylvania. "It's an uphill battle," he said.

He flew to Indiana, the scene of one of the two next primaries, before the polls closed in Pennsylvania.

"Now it's up to you Indiana," Obama told a rally in Evansville after Clinton won Pennsylvania.

The winner of the state-by-state primary race will become the Democratic party candidate in the presidential election in November. The next votes, in Indiana and  North Carolina, are set for May 6.

Clinton needed a clear win or her bid might have been over, analysts said. A loss or a narrow victory would have increased pressure on her to drop out of the race, because of Obama's lead in delegates.

Hillary Clinton hugs a supporter outside a polling station in Conshohocken, Pa., before winning the primary.
(Elise Amendola/Associated Press)

She went into Tuesday's vote with a slight lead in the state, and won, despite being outspent two-to-one by Obama.

At stake are 158 delegates, who will cast their ballots at the party convention to pick the presidential candidate in August.

An early report said she had won 38 delegates and Obama 34, with 86 still to be awarded. That gave Obama 1,682.5 delegates, and Clinton 1,547.5, the Associated Press calculated.

Clinton, who, like Obama, is a senator, had been expected to draw support from women, Caucasians, Catholics, older people and blue-collar workers. Obama had been expected to draw more support from the wealthy, young people and blacks.

Pennsylvania is the last big state to hold a primary before the voting ends on June 3, although there will be nine more primaries.

Last-minute ads

As the Pennsylvania contest neared its end, the Clinton campaign released ads featuring al-Qaeda leader Osama bin Laden, and asked Americans who they thought has "what it takes" to deal with wars in Afghanistan and Iraq, rising oil prices and a wavering economy.

Obama responded by accusing her of using "the politics of fear," and delivering an ad asking: "Who in times of challenge will unite us — not use fear and calculation to divide us?"

In the last major votes in Texas and Ohio six weeks ago, Clinton pulled off victories that kept her in the race.

With files from the Associated Press