President Barack Obama and Republican challenger Mitt Romney were campaigning in battleground states on Saturday, 10 days before an election that polls show is a dead heat.
Governor Romney held three rallies in Florida, whose 29 electoral votes are the biggest prize among states considered too close to call. He highlighted growing government debt.
President Obama spent the day in New Hampshire, whose four electoral votes could make a difference.
He criticised Governor Romney's record on taxes and fees as governor of Massachusetts.
Both campaigns are urging people to vote early and 18% of the electorate may have already done this.
The two candidates are in a statistical dead heat in the daily Reuters/Ipsos online tracking poll.
Mr Obama led Mr Romney by 47% to 45%, within the survey's margin for error.