OSHKOSH • US President Donald Trump questioned former vice-president Joe Biden's mental capabilities and mocked Senator Kamala Harris of California as an extreme liberal in three campaign rally-like appearances on Monday as Democrats began their national political convention nominally in Milwaukee, but largely online.

In front of Air Force One in Wisconsin, which delivered 10 critical electoral votes for the President's 2016 victory over Hillary Clinton, he said the 2020 election was a "fight for the survival of our nation and civilisation itself" and condemned Mr Biden as a puppet of the "radical left" in the Democratic Party. "You want to crush our economy," Mr Trump asked the crowd at the Oshkosh airport, "under the crazy socialist policies of sleepy Joe Biden and his boss Kamala Harris - Kamala - and his other boss, Nancy Pelosi - she's a beauty - and his ruler Bernie Sanders, crazy Bernie, or do you want to quickly rebuild the strongest economy in the history of the world?"

Mr Trump's re-election campaign has struggled to get traction amid the coronavirus pandemic that has devastated the US economy and forced cancellations and shutdowns across vast swathes of American life. The President's early dismissals of the virus threat and his administration's chaotic response have helped drive his poll numbers down to double-digit deficits against Mr Biden.

He pointedly chose Oshkosh, not far from Milwaukee, to counterprogramme four days of speeches from Democratic Party stars.

At a stop on Monday in Mankato, Minnesota, he gave an hour-long speech to a small crowd at the airport, accusing Mr Biden of wanting to raise taxes, weaken police departments, open borders, raise energy costs and lock people in their homes because of the pandemic. "He will kill the stock market," Mr Trump said. "He will kill everything that we're talking about today. You'd also abolish immigration enforcement, abolish bail, abolish the suburbs, abolish effective policing, abolish American energy and abolish the American way of life."

Earlier, he boasted about his "incredible" job confronting the spread of the virus and falsely said Mr Biden wanted to "lock all Americans in their basements for months on end, which would inflict permanent irreversible harm on our nation's children, families health and economy".

Mr Trump's first stop of the day was at the airport in Minneapolis, where there were protests and violence after the death of Mr George Floyd at the hands of a police officer in the city. He lashed out at Mr Biden and other Democrats for enabling "radical left anarchists" who looted parts of Minneapolis. "Everyone says, 'Oh, don't use that term, radical left," he said. "I go 'radical left anarchists!"

At an early-morning Fox News interview, he suggested Mr Biden's mental capacity was lacking. "Biden is shot. I'm telling you he's shot. There's something going on," he said. "Now with that being said, I don't underestimate anybody. Only a fool would do that."

He also called Ms Harris "a disaster" and misstated her positions by saying "she wants to take away everyone's gun. She wants to totally ban fossil fuels."

NYTIMES