US President Donald Trump's first tweet on Friday morning showed his confidence of winning the upcoming elections in November.

"Polls numbers are looking very strong. Big crowds, great enthusiasm. Massive RED WAVE coming!!!" Trump tweeted.

"Very good reviews on last night's @NBCNews Town Hall in Miami. Thank you!!!" he added.

Symbolising the deep chasm in US politics, Trump and his Democratic challenger Joe Biden participated in two separate town hall events flinging accusations against each other on Thursday. While Biden's town hall was hosted by ABC News in Philadelphia, Trump's 60-minute appearance in Miami was organised by NBC News.

With only 19 days left before the November 3 Election Day, Trump was hit with tough questions on his Covid-19 response and on race, while Biden faced questions on his past support for a controversial crime bill that hit minorities hard.

Biden's performance was gaffe-free, while Trump was often his combative self and there was nothing dramatic that could immediately impact the election.

Foreign policy hardly figured in the two events.

The second presidential debate, initially slated to be held in Miami on October 15, was cancelled after Trump refused to participate in a virtual face-off following his Covid-19 diagnosis. Biden had howewer, agreed to decision by the Commission on Presidential Debates over the virtual format.

The defining moment in Trump's hour-long event was when he unequivocally denounced White supremacists, which he had not done explicitly at his debate. He then challenged Biden to denounce the Antifa - the so-called anti-fascist movement - which is behind a lot of the violence and looting in recent months during the protests against police brutality and racism that is backed by the Democrats.

But he would not give a straight answer when asked about a fringe right-wing group called QAnon which spreads conspiracy theories about a "satanic" paedophile organisation with connections to Democrats. He said he did not know them, but it was good they were against paedophilia.

On his Covid-19 response he brought out his usual defence that he imposed the ban on China travel early, while Biden and others were against it, and was ambiguous about when his own coronavirus tests showing negativity had been conducted saying he could not remember.

Meanwhile, Biden's meeting moderated by President Bill Clinton's former aide and now an ABC anchor George Stephanopoulos was a more sedate affair.

The only foreign policy issue of significance in either meetings came when a Trump supporter asked him about the president's success in opening Israel to more Arab countries and Kosovo and Serbia normalising relations.

Giving Trump a grudging compliment, he said that the US was alone and insecure, estranged from NATO allies and added that "we are in a situation where in the Far East we find ourselves in the western Pacific, where we are isolated as well" with no mention of the Indo-Pacific where India has been asked to take on a greater role with Australia and Japan.

"China is making moves," he said.

Race issues also came up in the Biden meeting when a young man asked him about the crime legislations that he had supported while in Senate that imposed disproportionate sentences on minorities.

Biden admitted, "It was a mistake", but went on to defend it saying that the mistakes were at the local and state level and not federal.

Trump was asked by an African-American teacher about the risks young minority youth like her son and students face from police.

The President and Biden are still scheduled to face-off in the third presidential debate on October 22.