WASHINGTON:President Donald Trump planned to rally his supporters in the swing state of Pennsylvania on Tuesday, as the number of early ballots cast in the contest between him and Democrat Joe Biden passed 35 million with two weeks of voting to go.

Trump's trip comes the day before Biden's old boss - former President Barack Obama - is to campaign for the Democratic candidate in Pennsylvania, which will play an important role in deciding who wins the contest that ends on Nov. 3.

National opinion polls show Biden, the former vice president, holding a wide lead over Republican Trump, although the contest is closer in swing states that decide elections, including Florida, North Carolina and Pennsylvania.

Trump has gained some ground on Biden in Pennsylvania, according to a Reuters/Ipsos poll released on Monday, which showed the challenger leading by 49% to 45%, slightly narrower than a week earlier.

New data on Tuesday showed Biden maintaining his lead over Trump in Michigan, while the two were in a statistical tie in North Carolina.

Trump was due to hold a rally in Erie, in Pennsylvania's northwest corner, at 7 p.m. EDT (2300 GMT).

Biden has no events planned for Tuesday.

Underscoring the importance of the "Rust Belt" state, Obama was due to campaign for Biden at a "drive-in car rally" event on Wednesday in a Pennsylvania location yet to be announced. It will be Obama's first in-person campaign event for Biden, who served with him for eight years.

Trump's handling of the coronavirus pandemic, which has killed more than 220,000 people in the United States and thrown millions out of work, has taken a toll on his re-election prospects.

Despite rising cases of the highly contagious disease, which landed Trump in the hospital for three nights, he has resumed a heavy schedule of campaign travel, including rallies where his supporters pack together tightly, many not wearing masks.

Trump's path to victory is narrowing in the state-by-state race that determines who will occupy the White House after Jan. 20, 2021.

Five million more votes were cast over the past day, boosting early turnout to 35.5 million, according to the University of Florida's U.S. Elections Project. That total represents more than a quarter of the total vote in the 2016 presidential contest.

Early returns show registered Democrats outpacing Republicans in most states that track party affiliation. Trump has repeatedly characterized absentee voting as unreliable, although experts say it is as secure as any other method.

His campaign and the Republican Party have sought, with mixed success, to limit voting by mail in states that expanded it in response to fears of spreading COVID-19 at crowded polling places.

In Pennsylvania, his campaign has failed to prevent officials from setting up ballot drop boxes, a popular option in many other states.

VOTERS LINE UP IN WISCONSIN

Early in-person voting began in Wisconsin, Utah and Hawaii on Tuesday.

Wisconsin voters bundled up and braved temperatures as low as 30 degrees Fahrenheit (minus 1 degree C), to stand in line at polling locations in such cities as Milwaukee, where people waited about an hour, according to videos posted by media outlets.

"We're holding our breath, and I'm concerned about lines at early voting places," said Jay Heck, executive director of the nonpartisan voting rights group Common Cause in Wisconsin. "Voting does seem to be pretty robust. ... Every area - red counties and blue - there seems to be a lot of enthusiasm," he said in reference to counties that lean toward either of the parties.

Trump and Biden will face off in a final televised debate on Thursday, after Trump backed out of last week's planned appearance over a disagreement about the virtual format following his COVID-19 infection.

Organizers said on Monday a candidate's microphone would be muted to ensure his rival had a chance to speak for two minutes at the outset of every 15-minute debate segment - an attempt to head off the interruptions that marred the first matchup.

Trump's campaign objected to the rule change but said he would participate.

In Miami, where people gathered for the second day of in-person early voting, a police officer in uniform wore a "Trump 2020" face mask inside a polling location, according to the Miami-Dade Democratic Party chairman, who posted a photo of the officer. The Miami Police Department said on Twitter that "this behavior is unacceptable, a violation of departmental policy, and is being addressed immediately."