Opinion polls show the pair locked in a tight race, with Vice President Harris, 60, bolstered by strong support among female voters while former President Trump, 78, gains ground with Hispanic voters, especially men.

Voters overall view both candidates unfavorably, according to Reuters/Ipsos polling, but that has not dissuaded them from casting ballots.

More than 78 million Americans have already done so ahead of Tuesday's Election Day, according to the University of Florida's Election Lab, approaching half the total 160 million votes cast in 2020, in which US voter turnout was the highest in more than a century.

Control of Congress is also up for grabs on Tuesday, with Republicans favored to capture a majority in the Senate while Democrats are seen as having an even chance of flipping Republicans' narrow majority in the House of Representatives. Presidents whose parties fail to control both chambers have struggled to pass major legislation.

"In just two days we have the power to decide the fate of our nation for generations to come," Harris told parishioners at Greater Emmanuel Institutional Church of God in Christ in Detroit. "We must act. It's not enough to only pray; not enough to just talk."

Later in a rally in East Lansing, Michigan, she addressed the state's 200,000 Arab Americans, starting her speech with a nod to civilian victims of Israel's wars in Gaza and Lebanon.

"This year has been difficult, given the scale of death and destruction in Gaza and given the civilian casualties and displacement in Lebanon, it is devastating. And as president, I will do everything in my power to end the war in Gaza," Harris said to applause.

Many Arab and Muslim Americans as well as anti-war activist groups have condemned US support for Israel amid the tens of thousands of civilian deaths in Gaza and Lebanon, and the displacement of millions. Israel says it is targeting militant groups Hamas and Hezbollah.

Trump visited Dearborn, Michigan, the heart of the Arab American community, on Friday and vowed to end the conflict in the Middle East without saying how.

Instead of mentioning Trump by name, Harris chose to highlight her opponent's record during her last Sunday on the campaign trail.

Trump goes off script

Trump, at his first of three rallies on Sunday, frequently abandoned his teleprompter with off-the-cuff remarks in which he denounced opinion polls showing movement for Harris. He called Democrats a "demonic party," ridiculed Democratic President Joe Biden and talked about the high price of apples.

Trump, who survived an assassination attempt in July when a gunman's bullet grazed his ear in Butler, Pennsylvania, on Sunday complained to supporters about gaps in the bulletproof glass surrounding him as he spoke and mused that an assassin would have to shoot through the news media to get him.

"To get me, somebody would have to shoot through the fake news and I don't mind that so much," said Trump, who has long criticized the media and sought to rile public sentiment against them.

Last week he suggested prominent Republican critic, former congresswoman Liz Cheney, should face gunfire in combat over her hawkish foreign policy, leading an Arizona prosecutor to open an investigation.

Campaign spokesperson Steven Cheung issued a statement saying Trump's comment was not directed toward the media but rather, "It was about threats against him that were spurred on by dangerous rhetoric from Democrats."

Trump later spoke in Kinston, North Carolina, and in Macon, Georgia, where he seized on last week's jobs report that showed the US economy only produced 12,000 jobs last month.

He told a large crowd gathered in an amphitheater that the report showed that the United States was a "nation in decline" and he warned darkly without evidence of a potentially looming repeat of the 1929 Great Depression with "people jumping off buildings."

Senior Harris campaign officials have said her closing argument is designed to reach a narrow slice of undecided voters. That stood in contrast to Trump, who varied little from his standard speech aimed at inspiring his loyal supporters.

"Kamala's campaign is run on hate and demonization," Trump said.

Near the end of his Pennsylvania speech, Trump - whose false claims that his 2020 loss was the result of fraud inspired his supporters' Jan. 6, 2021, assault on the US Capitol - mused that he would have preferred not to have handed over power.

"We had the safest border in the history of our country the day that I left. I shouldn't have left. I mean, honestly, because we did so, we did so well," Trump said.

Trump said during his remarks that election results should be announced on Election Night, despite warnings by officials in multiple states that it could take days to ascertain the final outcome.

Democrats say they have plans in place should Trump try to prematurely claim victory this time.