• Barack Obama warns against overconfidence. His aide encouraged by early voting results
• John McCain says he sees momentum growing and adds stops in Western states on election day
Democrat Barack Obama and Republican John McCain raced through the battleground states of Ohio and Pennsylvania on Sunday, with Mr McCain struggling to overtake Mr Obama's lead in the final 48 hours of a gruelling White House campaign.
Mr Obama warned supporters against overconfidence during rallies in Ohio, one of about a dozen crucial battleground states that will decide Today's election to succeed unpopular President George W. Bush.
The Illinois senator leads Mr McCain in national opinion polls and in many key Republican-leaning states as a two-year campaign that has cost more than €1.5 billion draws to a close.
"Don't believe for a second that this election is over," Mr Obama told a crowd of more than 60,000 in Columbus. Another 80,000 greeted him in Cleveland, where rocker Bruce Springsteen warmed up the audience and introduced Mr Obama.
"We can't afford to slow down, sit back, or let up for one day, one minute, or one second in these last few days," said Mr Obama, who would be the first black US president. Mr McCain reached out to undecided voters in Pennsylvania, his best and perhaps last hope of stealing a Democratic-leaning state from Mr Obama as the two candidates search for the 270 electoral votes needed for victory.
He also visited Peterborough, New Hampshire, another state won by Democrats in 2004 and where he scored key wins in 2000 and earlier this year in the primary.
The Arizona senator is battling to overcome a strong challenge from Mr Obama in about a dozen states won by Mr Bush in 2004, and he and his top aides said he was closing the gap at the end.
"My friends, I've been in a lot of campaigns. I know when momentum is there," Mr McCain said in Wallingford, Pennsylvania. "We're going to win Pennsylvania and we're going to win this election. I sense it and I feel it and I know it."
Mr McCain's whirlwind day of campaigning featured two stops in Pennsylvania, the appearance in New Hampshire and a post-midnight rally with thousands of supporters in a Miami basketball arena. He'll winded up the race yesterday with stops in seven states, including his home of Arizona. "What we're in for is a slam-bang finish," Rick Davis, Mr McCain's campaign manager said on "Fox News Sunday."
"He's been counted out before and won these kinds of states, and we're in the process of winning them right now," Mr Davis said of big battleground states like Ohio, Florida and Virginia.
A flurry of new opinion polls on Sunday offered only slim evidence to back up Mr Davis' claim. One new survey showed Mr McCain slightly ahead in Ohio, although others showed Mr Obama leading.
Mr Obama has an edge in most other key battleground states, although his advantage has been whittled down in Florida, Virginia, Nevada and Pennsylvania. Both candidates drove home their main themes in the final days of the race, with Mr Obama linking Mr McCain to Mr Bush and adding a new twist with an advertisement tying Mr McCain to the equally disliked Vice President Dick Cheney.
"I'm delighted to support John McCain," Mr Cheney says in the ad, shot at a campaign event on Saturday in Wyoming. He also praises Mr McCain's running mate, Alaska Governor Sarah Palin. "That's not the change we need," the ad's announcer says.
Mr McCain renewed his attacks on Mr Obama as a liberal whose tax policies would hurt small businesses. Mr Obama has said he will raise taxes on those making more than €194,000 a year.
As Mr Obama boarded his campaign plane for Ohio on Sunday morning in Missouri, a reporter asked if he would hold a news conference. "I will. On Wednesday," he said. A campaign spokesman later said plans for a news conference were not firm but it would be sometime this week.
In Ohio, Mr Obama offered rare praise for Mr McCain, applauding his comic turn on NBC's Saturday Night Live.
"John McCain was funny yesterday on Saturday Night Live," Mr Obama said. "That's part of what politics should be about, being able to laugh at each other but also laugh at ourselves."