Harris slams Trump at campaign gathering

US Vice-President Kamala Harris, having secured backing from Congress' top Democrats, held her first presidential-style campaign rally in Wisconsin on Tuesday, where she sharply criticized Republican nominee Donald Trump.

Harris, 59, had moved quickly to shore up her likely nomination after President Joe Biden, 81, said on Sunday he would not seek reelection. Biden endorsed Harris that day and the vice-president's campaign picked up steam.

Harris wrapped up the nomination by winning pledges from a majority of the delegates, who may still vote for the candidate they prefer when the party picks its nominee next month at the Democratic National Convention in Chicago.

Biden, who came back to Washington after isolating at his home in Delaware with COVID-19, will address the nation from the Oval Office on Wednesday night to explain his reasons for dropping out of the race after intense pressure from his party.

Most Democratic lawmakers have lined up behind Harris' candidacy, including the party's leaders in the Senate and House Chuck Schumer and Hakeem Jeffries, who endorsed Harris on Tuesday at a joint news conference.

Democrats were looking to unify the party following a tumultuous month of infighting over whether Biden should remain the nominee.

"This campaign is not just about us versus Donald Trump; this is about who we fight for," Harris told an enthusiastic audience in West Allis, a Milwaukee suburb in Wisconsin.

"Donald Trump wants to take our country backward," she said. "Do we want to live in a country of freedom, compassion and rule of law, or a country of chaos, fear and hate?"

Wisconsin, along with Michigan and Ohio, is a crucial Rust Belt battleground state in the Nov 5 election.

'Brazen money grab'

Trump's campaign filed a complaint with the Federal Election Commission on Tuesday, arguing Harris could not legally take over the roughly $95 million funds raised by Biden's reelection campaign.

Harris undertook a "brazen money grab", said the filing by David Warrington, the campaign's general counsel.

In the filing, which was shared with Reuters, Warrington said Harris was in the process of committing what he described as "the largest campaign finance violation in American history".

Election regulators are unlikely to resolve the issue before the election.

Harris' campaign said it had raised $100 million since Sunday, when Biden announced his withdrawal, exceeding Biden's remaining tally in just a few days.

In a call with reporters on Tuesday, Trump criticized Harris' record on immigration since she was tasked by Biden with looking into the root causes of the migration surge.

"Kamala Harris was appointed border czar, as you know, in March 2021, and since that time, millions and millions of illegal aliens have invaded our country, and countless Americans have been killed by migrant crime because of her willful demolition of American borders and laws," Trump said on the call.

A YouGov poll on Monday showed Trump had a 15 percentage point lead on Harris on the issue of immigration.

Recent polls on voter preference overall are mixed.

Harris led Trump 44 percent to 42 percent among registered voters in a national Reuters/Ipsos poll conducted on Monday and Tuesday.

A recent YouGov poll showed Trump ahead 44 percent to 39 percent, among registered voters. And a Yahoo News poll had each candidate with 46 percent, in a contest that has five candidates.

Agencies contributed to this story.