MILWAUKEE, United States (AFP) — Donald Trump came under fire for violent rhetoric against a prominent Kamala Harris supporter Friday as the candidates held duelling rallies in the battleground of Wisconsin four days before the climax of the most volatile United States (US) presidential campaign in modern history.

More than 66 million Americans have already cast early ballots ahead of Tuesday’s election day. Opinion polls show Trump and Harris running dead even, with victory depending on who wins a majority of the seven swing states, including Wisconsin.

Both were campaigning in the state’s largest city Milwaukee.

Trump was holding a rally in the same venue where he celebrated the Republican Party nomination over the summer, delivering a triumphant acceptance speech just days after the 78-year-old had narrowly escaped an assassination attempt in Pennsylvania.

He was also due to meet with Arab-Americans in Dearborn, Michigan, hoping to exploit anger in the community over US support for Israel’s war in Gaza.

Harris — who only entered the race in July after President Joe Biden dropped out amid fears over his health — was to be joined by star rapper Cardi B in the latest of a series of high-energy rallies.

Wisconsin is part of the Democrats’ “blue wall” fortress in the Midwest, but the region could go either way — and with it the presidency.

The other path to victory could lie through winning swing states in the US West, where Trump and Harris both campaigned on Thursday.

As the contest draws to a close, Trump has upped his provocative rhetoric in a bid to fire up the base he needs to turn out in massive numbers.

On Thursday, at an event with Tucker Carlson — a leading right-wing influencer and conspiracy theorist who was fired by Fox News — Trump called Harris, 60, a “sleaze bag” and Biden a “stupid bastard”.

He also claimed, without evidence, that polls are already being rigged in the biggest swing state Pennsylvania — reinforcing expectations that, as in 2020, he will again refuse to accept the results if he is defeated.

But it was his comments about Liz Cheney, a formerly senior Republican leader who has become a supporter of Harris that stirred most controversy.

Citing her hawkish foreign policy views, Trump conjured the image of Cheney — daughter of former Republican vice president Dick Cheney — being shot multiple times.

“She’s a radical war hawk. Let’s put her with a rifle standing there with nine barrels shooting at her, OK? Let’s see how she feels about it. You know, when the guns are trained on her face,” Trump said.

Cheney responded, saying, “This is how dictators destroy free nations. They threaten those who speak against them with death.”

A handful of businesses and offices in downtown Washington began to board up windows on Friday in anticipation of potential unrest over the election.

The city witnessed violence four years ago when then-president Trump whipped up a crowd of supporters who stormed Congress in an attempt to halt certification of Biden’s victory.

Trump has focused his campaign on stirring fears about immigrant violence and pessimism over the economy.

Harris is running on warnings about an authoritarian Trump takeover, promising to help the middle class, and pushing back against Republican abortion curbs.

Economists say the US economy is actually in robust shape, shrugging off the last COVID pandemic cobwebs, with low unemployment and strong growth.

Figures released Friday showing drastically lower job growth in October, however, dented the Democrats’ messaging.

Only 12,000 new jobs were created, far below expectations. Economists said this was a blip, caused by knock-on effects from hurricanes and a strike at Boeing.

Adding to tensions, US social media is awash with disinformation that authorities say has been stirred by Russian operatives and amplified by US right-wing influencers — including Trump ally Elon Musk, the world’s richest man and owner of the X platform.

Much of Musk’s effort has involved pushing lies about non-citizen immigrants voting.

In the latest incident, the chief elections official for Georgia, another swing state, flagged as “fake” a viral video purporting to show a Haitian man who voted multiple times for Harris.