The US presidential election was set to shift into high gear on Monday as Republican John McCain and Democratic rival Barack Obama rallied supporters in battleground states after a rare day off.

McCain, a decorated war hero who had based much of his early campaign on the strength of his experience, wrestled last week for Obama's mantle of change with the help of his surprise vice presidential pick Sarah Palin.

The self-proclaimed mavericks vowed to use their history of fighting corruption to shake up and reform Washington at a series of campaign stops in the days following their crowning at the Republican National Convention on Thursday.

"In politics, there are some candidates who use change to promote their careers, and then there are those like John McCain, who use their careers to promote change," Palin to a cheering crowd in Wisconsin on Friday.

"We're going to win this election and let me offer a little advance warning to the old big spending, do-nothing me-first country second Washington crowd: change is coming. Change is coming," McCain said the next day in Colorado.

'No change from Bush'

Obama ridiculed McCain's promise of change and hammered the Arizona senator on the limping US economy, saying the Republican represented no change from Bush.

"John McCain, who is a good man and has a compelling biography, has embraced and adopted the George Bush economic platform," Obama said on ABC's "This Week."

The Illinois senator argued that voters would realise that the election was a choice between a new direction and discredited Republican policies.

"If they like what they've had over the last eight years, then they'll go with McCain. And if they don't like it, hopefully they'll go with me," he said on ABC's "This Week."

Obama's running mate Senator Joseph Biden meanwhile said that the idea that McCain was a change agent was "malarkey."

"Tell me one single thing they're going to do on the economy, foreign policy, taxes, that is going to be change," Biden said on NBC on Sunday.

McCain moves into lead

A new Gallup daily tracking poll found McCain had moved into a 48 to 45 percent lead ahead of the 4 November election — his best performance since May.

The Democrats have had a hard time targeting Palin, who is popular among social conservatives and has garnered public sympathy in the wake of the media's response to news that her 17-year-old daughter was pregnant and planned to keep the baby.

Senator Hillary Clinton, who narrowly lost the Democratic primary and was incredibly popular among white women, has also refused to criticise Palin even though the McCain campaign has actively targeted her disgruntled supporters.

But Clinton, who has kept a low profile since she dramatically ceded to Obama at the Democratic National Convention in late August, is expected to sharply attack McCain at three events in Florida on Monday.

McCain has been sharp in his criticism of Obama, warning on Sunday that his rival did not have good "judgment" or a record of challenging his own party's dogma.

"He never took on his party on a single major issue, I have taken them on a lot," McCain said on CBS "Face the Nation" Sunday as the candidates launched a flurry of interviews in the heated run-up to the 4 November election.

"I think I can make a strong case that whatever the issue, he doesn't have the judgment."

Neither headliners held rallies on Sunday although McCain and Palin introduced themselves to voters at a Mexican restaurant in New Mexico and a barbecue joint in Missouri and Biden spoke at a Montana high school on Sunday.

The Republican candidates had a rally planned in Missouri on Monday morning and a fundraising dinner in Obama's hometown of Chicago that evening.

Obama had two rallies planned in Michigan on Monday and another in Virginia on Tuesday. Biden will hold a town hall meeting in Wisconsin on Monday morning and rally in Iowa that evening.

AFP