Kamala Harris held a star-studded rally Thursday in swing state Georgia, where former US president Barack Obama and rock legend Bruce Springsteen joined her final push for voters ahead of November's nail-biter election.

Harris is cranking up the celebrity wattage -- including with Beyonce in Texas on Friday, according to reports -- at a series of concerts in battleground states in hopes of pulling away from rival Donald Trump.

Springsteen and Obama each delivered barbs aimed at the Republican as they addressed a crowd of thousands in Clarkston, just outside Atlanta.

"Donald Trump is running to be an American tyrant," Springsteen said, echoing concerns by Democrats -- as well as former members of Trump's administration -- about how Trump may misuse presidential power if reelected.

Bruce Springsteen performs on stage. Photo: AFP

The iconic singer, known for his socially conscious, working-class anthems, performed three songs including "The Promised Land" as part of a cameo designed to bolster Harris's blue-collar credentials.

Obama, the only Black president in US history who remains widely popular among Democrats, delivered a series of attacks at Trump -- questioning his business credentials and mocking his "word salad" speeches.

"We do not need four years of a wannabe king, a wannabe dictator, running around trying to punish his enemies," Obama said.

Harris emphasized her middle class roots -- drawing contrast with the billionaire Trump -- and said that she would prioritize battling inflation as president.

"We will build a future where we bring down the cost of living, and that will be my focus every single day as president of the United States," she said.

The predominantly Black audience -- a key electorate for Harris if she is to win Georgia -- was also addressed by actor Samuel L. Jackson and film director Spike Lee.

Large numbers of Americans, including about 2.2 million in Georgia, have already cast ballots in early voting, reflecting intense engagement ahead of Election Day on November 5.

'Fascist'

The vice president herself had raised the stakes in a CNN appearance late Wednesday when she said she considers 78-year-old Trump to be a "fascist" -- echoing a charge from a bombshell interview by the Republican's former chief of staff, John Kelly.

Trump, the oldest major presidential nominee in US history and the first to be running with a criminal record, is also casting the election as an existential battle for the United States.

But it will have profound personal implications too, given he is the subject of serious criminal probes into his attempt to overturn his 2020 election loss and his post-presidential hoarding of top-secret documents.

In a radio interview on his way to a rally in Arizona and then another in Nevada -- both swing states -- Trump announced that if elected he'd fire the special prosecutor overseeing his remaining cases in "seconds."

Donald Trump denies he praised Adolf Hitler. Photo: AFP

Speaking at the Arizona event, he conjured dark imagery of migrant violence and warned that America had become "a dumping ground" for dangerous and undocumented immigrants.

"We're like a garbage can for the world," Trump said at the Tempe rally, which was expected to focus on economic issues, particularly high housing costs.

But in his 55-minute address Trump made zero mention of home prices, opting instead to blame Harris for a "migrant invasion" that has overwhelmed American cities.

Beyonce

During a visit later to a Las Vegas bakery, Trump denied reports that he praised Hitler, telling reporters that his former chief of staff "made up stories."

At his Las Vegas rally, where he spoke for well over an hour, he claimed that counter to nearly all polls showing the race neck-and-neck, he was leading Harris "by a lot" in Nevada and other swing states expected to tip the national election.

He made similar unfounded assertions ahead of his 2020 loss to Joe Biden, and used those claims to justify his push to overturn the results.

US media reported Thursday that Beyonce -- whose hit "Freedom" is already the Harris campaign's signature song -- will join the Democrat when she visits Houston on Friday to highlight abortion rights.

Beyonce is expected to join Kamala Harris at a rally in Texas. Photo: AFP

Obama, 63, has been making his own headlining appearances in support of Harris in a slew of swing states, including Arizona, Pennsylvania, Wisconsin and Michigan.

The Harris campaign hopes the former president will reverse fears of eroding support among Black voters.

Harris, 60, is of mixed Black and South Asian heritage, and is vying to become the country's first female president.

Like Harris, Trump also heads Friday to Texas, where he is to deliver remarks on border security and record a podcast with comedian Joe Rogan.