US rivals in final dash for votes
Both men know they need to get voters out in swing states
The US presidential rivals are set to launch a hectic, final day of campaigning as they criss-cross the country in a last push for votes.
Republican John McCain will speak in seven states - from Florida in the east to his own state, Arizona, in the west.
Democrat Barack Obama will travel to Florida, North Carolina and Virginia - all won by the Republicans in 2004.
After one of the costliest campaigns in history, one of the men will on Tuesday be voted the 44th president of the USA.
The latest CNN/Opinion Research Corporation national survey suggests Mr McCain is trailing by seven points, while a Reuters/C-SPAN/Zogby poll has Mr Obama widening his lead slightly to 51% to 44%.
Other national polls indicate Mr Obama's lead over Mr McCain is holding steady at between five to 11 percentage points.
Both camps are keenly aware of the need to get voters out in the states that polls suggest remain in the balance.
FROM THE CAMPAIGN TRAIL
In my estimation 70% of the crowd had already been to the polling stations
Under the Electoral College system, states are apportioned votes based on their population, the biggest being California with 55 votes.
A candidate needs to win the magic number of 270 out of the 538 Electoral College votes to win the presidency.
Polls suggest the six closest state races on election day will be in Florida, Indiana, Missouri, North Carolina, Nevada and Ohio.
Mr McCain holds the lead in Indiana and North Carolina, but Mr Obama is ahead in the others, the latest polls from Reuters/C-SPAN/Zogby suggest.
"Obama's lead is very steady. He could be looking at a big day on Tuesday," said pollster John Zogby.
'The Mac is back'
Mr McCain remained defiant at a late night rally on Sunday in Miami, Florida.
"They may not know it, but the Mac is back! And we're going to win this election."
Various polls suggest Mr Obama has a two- to four-point lead over Mr McCain in vote-rich Florida.
"The Mac is back" McCain tells supporters
Despite the gloomy news from the opinion polls, Mr McCain has appeared more relaxed in recent days, and his campaign believes he is staging something of a comeback.
In Pennsylvania on Sunday, the Arizona senator told supporters in Wallingford: "We are going to win in Pennsylvania, we are going to win this election - I sense it and I know it.
"We are going to win here and we are going to bring real change to Washington."
The BBC's Matthew Price said Mr McCain had been focusing on conservative Democrats and independent-minded voters who lived in economically depressed areas of the state.
On Monday, Mr McCain is to make another appearance in Florida, before moving on to Tennessee, Pennsylvania, Indiana, New Mexico, Nevada and his home state of Arizona.
Backed by the Boss
In Ohio on Sunday, Mr Obama told supporters they were "two days from changing America".
Ohio, a narrow Republican win in 2004, has 20 votes under the electoral college system used in US presidential elections, making it one of the largest "undecided" states.
Bruce Springsteen introduces Barack Obama
Flush with a record-breaking fundraising operation, Mr Obama has been on the offensive all across the map, but on Sunday focused on Ohio, which has voted for the winning candidate in every presidential election since 1964. In Cleveland, the Illinois senator told a crowd of 80,000 who had gathered to hear him - and the singer Bruce Springsteen - that he was "feeling good".
"The crowds seem to grow and everybody's got a smile on their face," he said. "You start thinking that maybe we might be able to win an election."
Mr Obama has planned a lighter day of campaigning for Monday - with stops in Florida, North Carolina and Virginia.
Both campaigns have thousands of volunteers working flat-out manning phone banks, handing out brochures and knocking on doors ahead of Tuesday's election.
The BBC's Justin Webb, in Washington, says millions of Americans - perhaps a quarter of the total turnout - have already voted early, and that now the final rallies are in sight.
Some 130 million Americans are expected to cast a vote, in a higher turnout than in any election since 1960, our correspondent adds.
The final weekend's campaigning sprung surprises for each campaign.
On Saturday, it was revealed the Republican vice-presidential candidate, Sarah Palin, had been duped by a prank call.
For a full five minutes, a Canadian radio presenter successfully convinced the Alaska governor that he was French President Nicolas Sarkozy.
Meanwhile, it was reported that a Kenyan aunt of Mr Obama was living illegally in Boston, four years after an immigration judge rejected her request for asylum.