ATLANTA, United States (AFP) — Kamala Harris was scheduled to stage a star-studded rally late Thursday alongside former President Barack Obama and rock legend Bruce Springsteen as she launched a series of battleground state concerts to juice support in the final days of a nail-biting US presidential election.

The Atlanta, Georgia, rally — Harris’s first campaign stop with the only black president in American history — came as her bitter battle against Republican Donald Trump heads into the end game.

Large numbers of Americans, including two million in Georgia, have already cast ballots in early voting, reflecting intense energy ahead of November 5.

Springsteen, set to perform again for Harris in Philadelphia next Monday, will bring his brand of socially conscious, working-class anthems to get out the vote and boost Harris’s blue-collar credentials.

And Harris raised the stakes in a CNN appearance late Wednesday when she said she considers 78-year-old Trump to be a “fascist” — as charged in a bombshell interview by the Republican’s former chief of staff in the White House, John Kelly.

Trump, the oldest nominee in 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 certainly have profound personal implications, given he remains the subject of additional, 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 campaign rallies in Arizona and Nevada — both swing states — Trump announced that if elected he’d fire the special prosecutor overseeing his remaining cases in “seconds”.

Trump told conservative radio host Hugh Hewitt, an ardent supporter, that he would instantly fire the special prosecutor overseeing his unprecedented slew of criminal cases.

“Oh, it’s so easy. It’s so easy,” Trump said. “I would fire him within two seconds.”

The hiring and firing of special counsels — prosecutors who work at arm’s length from the Justice Department in politically sensitive cases — is the responsibility of the attorney general, who is in turn appointed by the president.

The contest remains a toss-up, with the two candidates jostling within the margin of error in polls from all the swing states set to tip the overall national result.

Harris is rolling out heavyweight celebrity backers in addition to Springsteen to break the deadlock.

US media reported Thursday that superstar Beyonce — whose song, Freedom, is already the Harris campaign signature music — will join the Democrat when she visits Houston, Texas, today.

Other big names helping Harris include rapper Eminem, Usher, and Megan Thee Stallion.

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

The Harris campaign hopes the former president — still one of the most popular Democrats on the national stage eight years after leaving office — will reverse eroding support among black voters.