Biden blasts ‘loser’ Trump as campaign slugfest intensifies

President Joe Biden needled "loser" Donald Trump Wednesday, in his first battleground campaign stop since the two rivals secured their parties' nominations for what promises to be one of the most rancorous elections in US history.

Speaking to supporters in Milwaukee in the crucial swing state of Wisconsin, the Democrat also blasted his hard-right Republican nemesis for describing immigrants as "vermin."

The return to the campaign trail came a day after incumbent Biden, 81, and Trump, 77, both won enough delegates to clinch their parties' nominations for a rematch in November.

"A lot of you helped me in 2020 and we made sure he was a loser. And we're going to make sure that happens again, right?" Biden told local supporters and volunteers in Milwaukee -- the same city where Trump and his party will hold the Republican National Convention in July.

Biden has taken to repeatedly calling Trump a loser, knowing it rankles the defeated former president, who still refuses to acknowledge he lost four years ago.

Wisconsin and Michigan, which Biden will visit on Thursday, were among the crucial states he flipped from Trump in their 2020 showdown and needs to win again to secure a second term.

Biden took on Trump over immigration, a key issue in the election with the Republican resorting to increasingly hardline rhetoric as he bashes the Democrat over record numbers of people crossing the border from Mexico into the United States.

The attacks underscored how bitter the next eight months of US politics promise to be, with the country's oldest ever pair of election candidates making no secret of the personal bitterness between them.

Both men lashed out at each other after their nomination wins on Tuesday. Trump called Biden the "Worst, Most Incompetent, Corrupt and Destructive President in the History of the United States."

Biden assailed Trump's "campaign of resentment, revenge, and retribution" and branded him a threat to democracy.

If reelected, Trump has pledged to be a "dictator" for his first day in power, when he says he will shut the border, order oil drilling and release supporters jailed for the January 6, 2021 US Capitol attack.

He has also promised the biggest ever mass deportation of millions of undocumented immigrants.

The political divisions in Washington have meanwhile paralyzed US foreign policy, alarming allies around the world.