Harris opens Saturday Night Live with 'keep Calm-ala'

Kamala Harris has made a surprise appearance on the Saturday Night Live TV comedy show just three days before her moment of truth with Republican rival Donald Trump in the US presidential election.

The vice president portrayed herself, appearing in a mirror opposite the actor who plays her on the show, Maya Rudolph, who was nervously preparing for a campaign speech.

Dressed identically in a black suit and pearls, the two traded variations on Democrat Harris' first name, saying Americans want to "end the drama-la" in politics "with a cool new step-mom-ala".

"Keep Calm-ala and carry on-ala," they said in unison.

"I don't really laugh like that, do I?" Harris asked, after Rudolph imitated her distinctive chortle.

"A little bit," Rudolph responded.

It was Harris' first time on the show, which has had other presidential candidates over its decades-long run.

"It was fun," she told reporters on the tarmac before flying to Detroit in the battleground state of Michigan.

Trump appeared during his first presidential bid in 2015 when he poked fun at his tendency to exaggerate and steer clear of policy specifics.

He also appeared in 2004, long before he entered politics.

A Trump aide said he did not know if he had been invited to appear this year.

Earlier on Saturday, Harris and Trump's planes shared the tarmac in Charlotte, North Carolina, as the two candidates held duelling events in the southern state - one of a handful that will determine the outcome of Tuesday's election (Wednesday Australian time).

It was the fourth day in a row that the candidates campaigned in the same state.

Only seven states are seen as truly competitive, but a poll released on Saturday showed Harris holding a surprise lead in Iowa, a state Trump won easily in the past two elections.

Trump and Harris stuck to familiar themes during their appearances.

Trump said he would deport millions of immigrants if elected and warned that if Harris won, "every town in America would be turned into a squalid, dangerous refugee camp".

Campaigning in Atlanta, Harris said Trump would abuse his power if he returned to the White House.

"This is someone who is increasingly unstable, obsessed with revenge, consumed with grievance, and the man is out for unchecked power," she said.

More than 75 million Americans have already cast ballots, according to the Election Lab at the University of Florida, in a sign of voter enthusiasm.

In North Carolina, the western counties that were devastated by Hurricane Helene appeared to be voting at roughly the same rate as the rest of the state, according to Catawba College political science professor Michael Bitzer.

At a later rally in Salem, Virginia, Trump said he ran for office to rescue the economy from "obliteration" even though it would have been easier to relax at one of his oceanfront resorts.

"I didn't need to be here today," he said.

"I could have been standing on that beach, my beautiful white skin getting nice and being smacked, being smacked in the face by a wave loaded up with salt water."

Trump was joined on stage by women from a local college swim team who have objected to competing against transgender athletes.

Some of Trump's TV ads have sought to capitalise on transgender controversies.