Donald Trump is leading in the US presidential election, broadly drawing more support than in 2020, but the outcome remains unclear in battleground states that will decide the victor.

Trump, bidding to become the first former president to return to the White House in more than 100 years, had won 211 Electoral College votes compared with 145 for his Democratic rival, Vice President Kamala Harris, with a third of the vote counted late on Tuesday (local time).

With Trump, 78, ahead in the battleground states of Georgia and North Carolina, Harris’s clearest path to victory remains through the “blue wall” of Michigan, Pennsylvania and Wisconsin.

A candidate needs a total of 270 votes in the state-by-state electoral college to claim the presidency.

Media outlet Decision Desk HQ was alone in projecting Trump would win Georgia and North Carolina. Other outlets and Edison had yet to call the two races.

Trump picked up much more support in the polls from Hispanics, traditionally Democratic voters, and among lower-income households that have keenly felt the sting of price rises since the last presidential election in 2020.

Trump won 45 per cent of Hispanic voters nationwide, trailing Harris with 53 per cent but up 13 percentage points from 2020, according to the provisional exit polls.

Currency and bond markets appeared to bet on Trump returning to power.

Common Cause, a nonpartisan watchdog group monitoring the US election, said all appeared to have gone “relatively smoothly” on Tuesday. But it cautioned many close races wouldn’t be called on Tuesday – and it may take days to count the votes.

“We need to prepare the public for this and that it is not abnormal – this only became abnormal when people made claims that everything should be available on election nights,” president and CEO Virginia Solomón said.

Democrats had only a narrow path to defend their Senate majority after Republican Jim Justice flipped a West Virginia seat on Tuesday.

The House of Representatives looked like a toss-up.

In Florida, a ballot measure that would have guaranteed abortion rights failed to reach the 60 per cent threshold needed to pass, according to Edison, leaving a six-week ban in place.

Nine other states have abortion-related measures on the ballot.

Nearly three-quarters of voters say American democracy is under threat, according to national exit polls from Edison, underscoring the depth of polarisation in a nation where divisions have only grown starker during a fiercely competitive race.

Trump employed increasingly apocalyptic rhetoric while stoking unfounded fears that the election system cannot be trusted.

Harris, 60, warned that a second Trump term would threaten the underpinnings of American democracy.

Hours before polls closed, Trump claimed on his Truth Social site without evidence that there was “a lot of talk about massive CHEATING” in Philadelphia, echoing his false claims in 2020 that fraud had occurred in large, Democratic-dominated cities.

In a subsequent post, he also asserted there was fraud in Detroit.

“I don’t respond to nonsense,” Detroit City Clerk Janice Winfrey told Reuters.

There is absolutely no truth to this allegation. It is yet another example of disinformation. Voting in Philadelphia has been safe and secure. pic.twitter.com/wMiPnAgO17

— Seth Bluestein (@SethBluestein) November 5, 2024

A Philadelphia city commissioner, Seth Bluestein, replied on X: “There is absolutely no truth to this allegation. It is yet another example of disinformation. Voting in Philadelphia has been safe and secure.”

Trump, whose supporters attacked the US Capitol on January 6, 2021, after he claimed the 2020 election was rigged, voted earlier near his home in Palm Beach, Florida.

“If I lose an election, if it’s a fair election, I’m gonna be the first one to acknowledge it,” Trump said.

His campaign has suggested he may declare victory on election night even while millions of ballots have yet to be counted, as he did four years ago.

Millions of Americans waited in orderly lines to cast ballots. There were only sporadic disruptions reported across a handful of states, including dozens of bomb threats in Georgia, Michigan and Wisconsin, that the FBI said appeared to originate from Russian email domains.

Trump was watching the results at his Mar-a-Lago club before speaking to supporters at a nearby convention centre.

Harris was due to speak to students at Howard University, a historically black college in Washington where she studied.

“To go back tonight to Howard University, my beloved alma mater, and be able to hopefully recognise this day for what it is, is really full circle for me,” Harris said in a radio interview.

Tuesday’s vote capped a dizzying race churned by unprecedented events, including two assassination attempts against Trump, President Joe Biden’s surprise withdrawal and Harris’ rapid rise.

-with AAP