Kamala Harris, Donald Trump trade blows on US election campaign trail

US Vice President Kamala Harris cast herself as the “underdog” in the US presidential race and called her Republican opponent Donald Trump “just plain weird”, while Trump labelled Harris “low IQ” and “radical”, as the rivals hit the campaign trail.

Their duelling public appearances capped a whirlwind week in which Harris ascended to the top of the Democratic ticket after President Joe Biden, 81, dropped his re-election bid under mounting pressure from his fellow Democrats.

A series of polls indicate Harris’ entry erased the lead Trump had enjoyed over Biden in a matter of days.

Harris, speaking at a private fundraiser headlined by singer-songwriter James Taylor in Pittsfield, Massachusetts, said much of the rhetoric coming from Trump and his running mate, US Senator JD Vance, was “just plain weird”.

Her use of the word “weird” to describe her opponents was part of a new strategy from Democrats.

The Harris campaign called Trump “old and quite weird” following his appearance on Fox News on Thursday, and at least one supporter showed up outside Saturday’s event holding a sign proclaiming “Trump is weird.”

As she did during a blitz of campaign stops this week, Harris again contrasted her background as a prosecutor with Trump’s record as a convicted felon and said her bid was about the future, while Trump wanted to return the country to a “dark past”.

Trump addressed a cryptocurrency conference in Nashville, part of a broader Republican effort to court crypto enthusiasts ahead of the November 5 election.

He compared the young sector to the steel industry of a century ago and vowed to make the US the “crypto capital of the world”, a far cry from his stance in 2021, when he called bitcoin a “scam”.

Trump warned that China and other countries would embrace crypto if the US did not and promised industry-friendly regulations if elected.

China currently bans cryptocurrency.

The former president was scheduled to rally later on Saturday in St Cloud, Minnesota.

The site of the event, an 8000-seat hockey arena, complies with the US Secret Service’s recommendation that he avoid large outdoor events following an attempt on his life at a rally in Pennsylvania two weeks ago.

Trump said on Saturday in a post on his Truth Social site that he would continue to hold outdoor rallies, and he believed the Secret Service was capable of protecting him.

Minnesota has not chosen a Republican presidential candidate in 52 years, but the Trump campaign had viewed it as increasingly within reach after Biden’s poll numbers dipped following his disastrous June 27 debate performance.

Harris’s takeover, however, has re-energised a campaign that had faltered badly amid Democrats’ doubts about Biden’s chances of defeating Trump, 78, or his ability to continue to govern should he succeed.

Harris, the first Black woman and first Asian American to serve as vice president, raised more than $US100 million ($A152 milion) in the 36 hours after Biden’s departure.

Saturday’s fundraiser brought in more than $US1.4 million from some 800 attendees, her campaign said.

Trump and Vance, 39, have attempted to tie Harris to what they say is the Biden administration’s failure to corral high inflation and stem a surge of migrants at the southern border with Mexico.

Trump asserted that Harris was “even worse” than Biden in his conference remarks.

Trump’s rally on Saturday follows his speech at a conservative gathering on Friday, when he told Christians that if they vote for him in November, “in four years, you don’t have to vote again”.

“We’ll have it fixed so good, you’re not gonna have to vote.”

Trump campaign spokesperson Steven Cheung did not directly address Trump’s remarks when asked to clarify them.