Trump has failed Americans amid COVID-19 pandemic: Biden

"What happened? Now it's almost July, and it seems like our wartime president (Donald Trump) has surrendered, waved the white flag and left the battlefield," Biden said in an address in a high school in Wilmington, Delaware on Tuesday.

The former Vice President used the same metaphor that Trump himself used in March when he declared himself a wartime President in the fight against COVID-19.

Biden said that month after month many, like him, have urged Trump to "step up and do his job" but added that "he failed us".

"We can't continue half wearing masks and half rejecting science. We can't continue half with a plan and half just hoping for the best," he said.

In that regard, Biden lamented that the Trump administration has left the decision to reopen economies and other issues pertaining to the epidemic to state and local authorities.

"We need real plans, real guidelines, with uniform nationwide standards, to help us chart our economic reopening. Whatever we've been doing now is not working. The state-by-state approach will only produce confusion and slow any progress," he said.

In Biden's opinion, there should be a clear message from the federal government that "everyone needs to wear a mask in public, period".

"Wear a mask. It's not just about you. It's about your family. It's about your neighbors. It's about your colleagues. It's about keeping other people safe," he added.

Biden said that if Trump had listened to health experts and the recommendations he had made a few months ago, the epidemic would not have spread so rapidly.

"It didn't have to be this way," he said.

The latest polls indicate that Biden is likely to win the presidential election on November 3.

A poll published on June 26 indicated that Trump's approval ratings were at their worst level (40 per cent) following protests against police brutality in the US and amid a surge in coronavirus infections in the country.

A record 58 per cent of voters disapprove of the job Trump's doing at the White House, according to a new survey conducted by the Marist Institute for Public Opinion together with the National Public Radio and PBS NewsHour.

As of Wednesday morning, The US accounted for the world's highest number of infections and fatalities with 2,629,372 and 127,322, respectively, according to the Johns Hopkins University.