US President Donald Trump and Democratic challenger Joe Biden will hold duelling prime-time town halls instead of a second debate, which was to have been held virtually, as early voters continued to swamp polling places.
Trump pulled out of the scheduled debate when the commission in charge of organising the event said it would be held virtually after he contracted the coronavirus. A final debate is still scheduled for 22 October in Nashville, Tennessee.
With less than three weeks to go until the 3 November vote, the Republican president is searching for ways to change the dynamics of a race in which Biden has a double-digit advantage in some national polls.
More than 17 million Americans have cast ballots either in person or by mail so far, representing 12.5 percent of the total votes counted in the 2016 general election, according to the US Elections Project at the University of Florida.
Voters are seeking to avoid in-person lines on Election Day to stay safe as coronavirus infections and hospitalizations continue to rise, but are also concerned about the possibility that Trump will challenge widely used mail-in ballots, after he claimed without evidence that they are fraudulent.
North Carolina, a highly competitive state, began more than two weeks of in-person early voting on Thursday.
Video from local media showed large numbers of people waiting for the polls to open in Greensboro and Winston-Salem, and gathering in the pre-dawn hours to vote at two arenas in the state's largest city of Charlotte.
Gerry Cohen, a member of the election board in the county that includes most of the city of Raleigh, reported more than 400 people waiting in line at a community centre before polls opened.
"I've never seen this many in line here," he said on Twitter.
Trump's campaign is counting on a surge of last-minute votes. But Reuters/Ipsos polling conducted between 9 October and 13 October shows there are far fewer undecided likely voters this year - around 8 percent - and they are just as likely to pick Biden as they are Trump.
Four years ago at this stage of the campaign, more than twice as many people were similarly wavering between Trump and his Democratic opponent, Hillary Clinton.
The Reuters/Ipsos polling shows Biden holding a 10 percentage-point lead nationally, with a tighter margin in the battleground states that will help decide the election.
Both candidates have been visiting those states this week, with Trump holding rallies in Florida, Pennsylvania and Iowa and Biden travelling to Ohio and Florida.
Trump has pulled into a statistical tie with Biden in Florida, a key battleground, with 47 percent support versus Biden's 49 percent, and a credibility interval of 4 points, a Reuters/Ipsos opinion poll showed.
Today's town halls, in which each candidate will field questions from voters, will take place at 8pm EDT (1pm NZT).
The Biden campaign said two people involved in the campaign had tested positive for Covid-19, including one on the staff of US Senator Kamala Harris, Biden's running mate.
Although neither Biden nor Harris was in close contact with the people, the campaign said it was cancelling Harris' travel until after Sunday.
"This shows how seriously we take Covid, how we have since March done everything in our power as a campaign to ensure the safety of our staff and volunteers and voters," Biden's campaign manager, Jen O'Malley Dillon, told reporters on a call.