US President Donald Trump has conducted a three-state campaign blitz after voting early in Florida, reports BBC.
He hopped between rallies in North Carolina, Ohio and Wisconsin on Saturday as he sought to make up ground against his Democratic challenger Joe Biden.
Mr Biden, who holds a steady lead in national polls, campaigned in Pennsylvania, another key state.
Some 57 million votes have already been cast, a record spurred by the pandemic.
The Republican president has continued to hold packed rallies despite a new surge in coronavirus infections that is particularly affecting the Midwest - home to several electoral battlegrounds that could decide the election.
Speaking in Lumberton, North Carolina, Mr Trump said America's coronavirus epidemic had been blown out of proportion, and mocked his Democratic rival for making ominous warnings about a bleak winter.
In contrast, Mr Biden held a drive-in rally in Bristol, Pennsylvania, where he told supporters: "We don't want to become superspreaders."
Meanwhile, the chief of staff for Vice-President Mike Pence has tested positive for Covid-19 but Mr Pence and his wife have tested negative, a spokesperson said. They plan to continue their busy campaign schedule, despite Mr Pence being a close contact of an infected person.
With just 10 days to go until the 3 November election, Joe Biden holds an average eight-point lead in national polls over Donald Trump.
But the race is much closer in several important swing states.
Most US states lean heavily towards one party or the other, so presidential candidates usually focus on a dozen or so "battleground" states where either of them could win.
States like Michigan, Wisconsin, Pennsylvania, Florida, Ohio and North Carolina are viewed as the most influential because they have historically swung between Republican and Democrat candidates. They also have high numbers of electoral college votes, which decide the outcome of the election.
After his three-state blitz on Saturday, including a late-night appearance in Waukesha, Wisconsin, the president will appear in New Hampshire on Sunday.
He is then scheduled to appear at two rallies in Pennsylvania on Monday, before making his way to Michigan, Wisconsin and Nebraska on Tuesday.
Mr Biden only has a narrow lead over Mr Trump in key battlegrounds, with Florida and North Carolina looking particularly tight, according to polling averages.
The Biden campaign focused on Pennsylvania on Saturday - holding two drive-in rallies there.
The Democrats won Pennsylvania in every presidential election from 1992-2012 but Mr Trump took the state by a 0.7% margin over Hillary Clinton in 2016.
Reflecting the importance of the Rust Belt state, Mr Biden, who was born there, told supporters: "It may come down to Pennsylvania. And I believe in you. I believe in my state."
Meanwhile, former President Barack Obama has been campaigning for Mr Biden in Florida.