Republican John McCain sought to revive his White House hopes in the symbolically named town of Defiance on Thursday as grim new figures on the US economy boosted Democratic rival Barack Obama.

With just five days of campaigning left, McCain launched a bus tour of the crucial battleground of Ohio seeking to rally support in a state which has suffered nearly 100 000 job losses in the past 12 months.

The former Navy pilot exhorted supporters gathered at a high school to fight for every last vote on 4 November.

"We're a few points down, but we're coming back," McCain said, as polls showed Obama enjoying a formidable position in a slew of highly contested states the Republican needs to win.

"I've been fighting for this country since I was seventeen years old, and I have the scars to prove it," McCain (72) said. "I'm not afraid of the fight, I'm ready for it."

Gloomy economic data

But McCain's tour got underway in this picturesque Midwest town against a backdrop of gloomy economic data which suggested a recession may be looming, as the government reported a 0.3 percent contraction in the third quarter.

His campaign warned Obama's economic manifesto would make things worse.

"Today's announcement ... confirms what Americans already knew: the economy is shrinking," McCain adviser Doug Holtz-Eakin said in a statement. "Barack Obama would accelerate this dangerous course."

But Obama (47) pounced and said at a rally in Sarasota, Florida that his rival would pursue what he sees as failed Republican economic policies.

"If you want to know where John McCain will drive this economy, just look in the rear-view mirror. Because when it comes to our economic policies, John McCain has been right next to (President) George Bush," he said.

"He's been sitting there in the passenger seat, ready to take over, every step of the way," Obama told more than 13 000 supporters at a sports stadium.

McCain has struggled to compete with Obama on economic policy as polls show the issue remains the overwhelming concern for voters.

The issue was the dominant theme of Obama's 30-minute infomercial which aired on a string of US television networks on Wednesday night, pulling in almost 22 percent of US households, according to preliminary figures by Nielsen Ratings on Thursday.

'The greatest job interview in the world'

The Democratic nominee followed up immediately with a late-night rally with former president Bill Clinton, who is highly popular in swing state Florida, and Obama was spending Thursday sweeping through normally Republican territory.

"The presidential campaign is the greatest job interview in the world. And on Tuesday, you get to make the hire," Clinton said, contrasting the economic prosperity of his own 1990s tenure to the crisis now sweeping the nation.

Latest polls showed Obama with a solid lead nationally, and across the electoral map, and even pushing McCain in his home state of Arizona.

Rasmussen's daily tracking poll on Thursday put Obama up five points, 51 to 46 points, reversing a tightening which cut the gap to three points on Wednesday.

Another new survey by Mason-Dixon for MSNBC found that Obama was surprisingly pulling within reach of McCain on his home turf of Arizona, with the Republican leading 48 to 44 percent.

But there was a glimmer of hope for McCain, as the same firm had him only four points back by 47 percent to 43 percent in Pennsylvania, a Democratic state in recent elections he must flip to have a chance of reaching the White House.

Other recent surveys in Pennsylvania though have given Obama a wider lead.

Obama's campaign meanwhile announced that former vice president Al Gore, who many Democrats believed was cheated out of the White House by the 2000 recount debacle in Florida, would campaign in the state for the Illinois senator on Friday.

AFP