Taunts fly ahead of key US vote

Opinion polls suggest Mrs Clinton's lead in Pennsylvania has narrowed

White House hopefuls Hillary Clinton and Barack Obama have traded jibes in a surge of negative campaigning ahead of the Democratic primary in Pennsylvania.

She accused him of helping Republican rival John McCain's campaign while he talked of her "slash and burn" tactics.

She needs a strong win to stay in the race for the Democrats' presidential ticket and polls suggest a close vote.

Meanwhile Mr McCain, on a visit to deprived areas, said there should be no "forgotten places" in America.

'Cheering on McCain'

Monday saw the Democratic rivals kicking off their campaigns Scranton, a Democratic, working-class town in north-east Pennsylvania.

DEMOCRATIC DELEGATES Barack Obama: Pledged delegates: 1,414 Super-delegates: 231 Total: 1,645 Hillary Clinton: Pledged delegates: 1,250 Super-delegates: 257 Total: 1,507 Source: AP estimates on 21 April Q&A: US election delegates Pennsylvania voters' views

Over the weekend, Mrs Clinton hit out at Mr Obama after he said Mr McCain would make a better president than George W Bush.

"We need a nominee who will take on John McCain, not cheer on John McCain, and I will be that nominee," she said.

She also struck out at a new Obama advertisement that criticises her health care plan, telling a rally in York, Pennsylvania: "Instead of attacking the problem, he chooses to attack my solution."

Mr Obama told a Pittsburgh radio station he was predicting not a win, but a close result.

"I'm predicting it's going to be close and that we are going to do a lot better than people expect," he said.

Earlier, on a railway tour of the state, he challenged Mrs Clinton's "slash-and-burn, say-anything, do-anything special interest-driven politics". "Trying to score cheap political points... doesn't make for good government," he said.

Mr Obama says Mrs Clinton is trying to score cheap political points

The candidates are now so close that neither is expected to win sufficient delegates to the party's national convention in August to seal the nomination, and are courting 800 or so unelected "super-delegates".

Pennsylvania provides a key test for Mrs Clinton's argument that despite Mr Obama's overall lead, only she will be able to secure wins in critical large states come the presidential election.

The state returns 158 delegates to the convention.

A poll released on Sunday by MSNBC/McClatchy, showed Mrs Clinton holding a five-point lead over Mr Obama in Pennsylvania - 48% to 43% -down from her once double-digit advantage.

There has been increasing pressure from senior Democrats for a swift resolution to the deadlock, fearing the prolonged battle will damage the eventual candidate's success against Mr McCain.

'False promises'

On campaign financing, new figures show Mr Obama raised $41m in March, to $20m for Mrs Clinton and $15m for Mr McCain.

John McCain will also visit Ohio, Kentucky and Arkansas shortly

Mr Obama, spending heavily in Pennsylvania, had a $42m war chest for April while Mrs Clinton had $9m. Mrs Clinton also reported a debt of $10.3m.

Mr McCain meanwhile evoked the spirit of civil rights marchers when he appealed for a new spirit of change on a visit to Selma, the Alabama town where peaceful black protesters were savagely beaten back by police in 1965.

"There must be no forgotten places in America, whether they have been ignored for long years by the sins of indifference and injustice, or have been left behind as the world grew smaller and more economically interdependent," he said.

He added that the "time for pandering and false promises" was over, in what analysts say was a veiled attack on his Democratic rivals, especially Mr Obama.

Mr McCain earlier won enough support in the Republican primaries to become his party's undisputed candidate in the November election.