Presumptive Democratic presidential candidate Joe Biden denounced Donald Trump's presidency and the gnawing problems of racism and inequality in the United States, during a meeting with black religious and political leaders in the wake of unarmed African American George Floyd's death at the hands of police.

"The band aid has been ripped off this pandemic and this president," Biden said, referring to the coronavirus, which has claimed disproportionately more lives among blacks and Hispanics, and his billionaire Republican rival's attitude toward minorities.

"Nobody can pretend any longer what this is all about," said Biden, who sought to present himself as a unifier at the meeting hosted by a church in his hometown of Wilmington, Delaware.

"Hate just hides. Doesn't go away. And when you have somebody in power who breathes oxygen into the hate under the rocks, it comes out from under the rocks," he said.

"It matters what the president says," Biden added. "It encourages people to bring out the vitriol."

The 77-year-old Biden, who served as president Barack Obama's vice president, recalled Trump's comments after clashes in Charlottesville, Virginia in 2017 between white supremacists and anti-racist counterprotesters.

A white supremacist had rammed his vehicle into a crowd of demonstrators, killing a young woman.

But the president said there were "very fine people on both sides."

Biden promised the black leaders at the meeting that, if elected in November, he would create a police oversight commission in his first hundred days in office.

Wearing a mask and taking notes after a prayer was said, Biden mostly listened in silence for about an hour as audience members spoke, some about the death in Minneapolis last week of George Floyd, who lost consciousness as a police officer pinned him down with a knee on his neck.

Several participants urged Biden to choose a black running mate, who would become the nation's first African American vice president, if he won.

"I promise you there are multiple African American candidates who are being considered," he said.

It was the first time Biden had participated in person in such a public gathering since mid-March, when the coronavirus pandemic abruptly paralyzed his campaign.