Trump calls for investigation of Biden, heads to Pennsylvania

United States President Donald Trump has called on the US attorney general to investigate his "criminal" Democratic opponent Joe Biden.

Polls show Trump down or in a tight contest in most of the swing states that decide presidential races, but he believes his frenetic campaigning will give him new momentum for the November 3 presidential election as he heads Tuesday to a rally in the key state of Pennsylvania.

"Things are changing fast," Trump told the Fox & Friends programme Tuesday, claiming that his own polling showed Biden is "imploding."

Notably, just over two weeks ago Trump was in hospital with Covid-19 and Biden had the field to himself, hammering home his central message that the Republican president has failed the country on managing the coronavirus pandemic.

Biden has, however, disappeared from the campaign trail, apparently to prepare for the debate.

Trump's current attack centres on a conspiracy theory about the Biden family's business activities. Crowds at Trump's rallies have even repurposed the old anti-Clinton chant of 2016 for Biden, shouting "lock him up."

According to Trump, Biden's personally troubled son Hunter sold access to his father in Ukraine and China when he was vice president to Barack Obama.

Trump Tuesday called Joe Biden "a criminal" and demanded on Fox News that the attorney general, Bill Barr, "act and act fast."

"This has to be known about before the election," Trump said.

While Biden continues to try and focus on Trump's handling of the pandemic -- depicting him as an irresponsible leader who panicked -- the president is milking frustration in places like Pennsylvania with the economic impact of shutdowns and social distancing.

"We will never shut down" again, Trump promised Tuesday -- a message he will likely repeat loudly at the rally.

According to a new poll from The New York Times/Siena College, Biden has a nine-point lead nationally.

Pennsylvania is one of the half dozen states that Trump more or less has to win to hold on to the presidency. Polls show Biden ahead, though a Reuters/Ipsos poll this week showed the gap narrowing slightly.

Trump is the first president to run for reelection after being impeached.

(with inputs)