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, has won 211 Electoral College votes compared with 145 for his Democratic rival, Vice President Kamala Harris, with a third of the vote counted.

With Trump holding leads in battleground states 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 at least 270 votes in the 538-member, 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.

But the race, as expected, was coming down to seven swing states: Arizona, Georgia, Michigan, Nevada, North Carolina, Pennsylvania and Wisconsin.

In Georgia, Trump had opened up a 52 per cent to 47 per cent lead with 77 per cent per cent of the estimated vote tallied, according to Edison.

Control of both chambers of Congress is also up for grabs.

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 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.

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 told reporters.

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, with only sporadic disruptions reported across a handful of states, including several non-credible bomb threats 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.

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.

No matter who wins, history will be made.

Harris, 60, the first female vice-president, would become the first woman, Black woman and South Asian American to win the presidency.

Trump, 78, the only president to be impeached twice and the first former president to be criminally convicted, would also become the first president to win non-consecutive terms in more than a century.