By Eliyahu Kamisher, Sophie Wingate and Cristina Maza

Washington - US President Donald Trump and Democratic challenger Joe Biden held rival televised town halls on Thursday, forcing voters to choose who to watch after the second presidential debate was cancelled.

Both candidates were questioned on aspects of the coronavirus pandemic, which has become a key issue during the campaign and shows the differences and disagreements between them.

When asked if his opinion on wearing masks has changed since his coronavirus diagnosis, Trump said no, adding that he supports masks but then falsely claiming that 85 per cent of mask-wearers are infected with the virus.

Biden used his event to attack the president on his handling of the coronavirus pandemic, while pitching himself as the president who will unite the country after a divisive four years under Trump.

During his event broadcast on NBC the president was then asked about his personal debt, which is a staggering 421 million dollars, according to a report in The New York Times.

Trump dismissed the report, but then appeared to confirm the number, saying that his debt is a "small percentage" compared to his net worth.

The president's town hall was scheduled after he declined to participate in the second presidential debate after it was moved to a virtual event due to his coronavirus diagnosis.

During the event Trump also claimed that he was not familiar with the QAnon conspiracy movement, but then appeared to provide tacit support for the far-right belief system, which falsely claims that Trump is fighting against a global elite of paedophile Satanists operating a child trafficking ring.

"I know nothing about QAnon," Trump said when asked to denounce the conspiracy.

"What I do hear about it, is they are very strongly against paedophilia, and I agree with that. I mean I do agree with that and I agree with that very strongly."

Biden was asked about packing the Supreme Court - a term which means to add judges - if the Democrats sweep the November election, gaining not only the White House, but also a majority in the Senate, while keeping control of the House.

Liberals are calling for Biden to pack the court since Trump has nominated Amy Coney Barrett, swaying the court's balance to 6-3 between conservatives and liberals. Critics of the practice say it would politicize the court in an unprecedented manner.

Biden said he is "not a fan" of court packing, but he is opening to supporting packing if Republican's in the Senate confirm Trump's conservative Supreme Court pick before the November 3 election.

Biden said he would clarify his position before the election.

A second and final presidential debate is scheduled for October 22, less than two weeks before the November 3 election, with Trump currently trailing Biden by a significant margin in the polls.

The Republican president seems to be pinning his hopes on his rallies as he seeks to boost enthusiasm among his base and turn out the vote, swiftly returning to the campaign trail after recovering from the coronavirus.

Biden is also outraising and outspending the Republican president on campaign ads. Biden raised 383 million dollars in September, after hauling in 364.5 million dollars the previous month.

The former vice president tweeted on Thursday that he was "incredibly humbled" by the "astounding" amount.

To every person who chipped in a few dollars last month — thank you. Because of your support, we raised an astounding $383 million. I'm incredibly humbled.

There's still more work to be done, but I wanted to share the good news with Trimicka, one of our grassroots supporters. pic.twitter.com/f9hIPT6PTW
— Joe Biden (@JoeBiden) October 15, 2020

By comparison, Trump raised 210 million dollars in August. His campaign has not disclosed his September haul.

Biden's running mate, Senator Kamala Harris, has cancelled campaign travel until next week after two people involved in the campaign tested positive for the coronavirus.