Joe Biden called out the "underlying racism" in America Thursday as he sought to soothe the protest-scarred Midwestern city of Kenosha, where the presidential hopeful spoke with a black father shot in the back by a white policeman.

Biden sat down for a private talk with Jacob Blake's father and other relatives, and revealed later that he had spoken for about 15 minutes by telephone with Blake as the 29-year-old was recovering in hospital.

"He talked about how nothing was going to defeat him, how whether he walked again or not, he was not going to give up," Biden said of Blake, whose lawyers say he is likely paralyzed from the waist down.

Describing himself repeatedly as an optimist, Biden -- speaking through a face mask -- told a small community gathering in Kenosha that the majority of Americans support the Black Lives Matter movement for racial equality.

Democratic US presidential candidate Joe Biden, with his wife Dr Jill Biden waves as he boards his plane in Delaware bound for Kenosha Wisconsin, the protest-hit city that President Donald Trump visisted two days earlier
Democratic US presidential candidate Joe Biden, with his wife Dr Jill Biden waves as he boards his plane in Delaware bound for Kenosha Wisconsin, the protest-hit city that President Donald Trump visisted two days earlier AFP / JIM WATSON

But he also warned that President Donald Trump has fueled the racial animus which has roiled the nation in recent months.

"Not all his fault," but Trump's heated and racially charged language "legitimizes the dark side of human nature," Biden said at Grace Lutheran Church, where a crowd of mostly-masked supporters gathered outside.

The president's rhetoric has exposed "the underlying racism that is institutionalized in the United States, and still exists, and has existed for 400 years," he added.

"I promise you, win or lose... I'm going to go down fighting the good fight for racial equality," Biden said, adding: "We're not going to go down."

The optics in Wisconsin offered a contrast from two days earlier when Biden's Republican rival brought his law-and-order message to Kenosha, where he survey damage and met law enforcement and business owners.

US President Donald Trump rallied voters in North Carolina on September 2, 2020, two months before the presidential election against his Democratic rival Joe Biden
US President Donald Trump rallied voters in North Carolina on September 2, 2020, two months before the presidential election against his Democratic rival Joe Biden AFP / MANDEL NGAN

Unlike Biden, Trump did not speak with Blake or his family, and he visited in defiance of pleas by the mayor and state governor, both Democrats, who feared that his presence would stoke tensions.

During Trump's meeting with police, he equated the demonstrations demanding racial justice with "domestic terror" by violent mobs.

Biden's visit, his first major trip since June due to months of coronavirus-driven lockdown and restrictions, marks an intensification of his presidential campaign two months before the US election.

A crowd gathered outside Grace Lutheran Church in Kenosha, Wisconsin on September 3, 2020, as Democratic presidential candidate Joe Biden joined a round table with community leaders to discuss recent racially charged protests and a path forward
A crowd gathered outside Grace Lutheran Church in Kenosha, Wisconsin on September 3, 2020, as Democratic presidential candidate Joe Biden joined a round table with community leaders to discuss recent racially charged protests and a path forward AFP / JIM WATSON

The campaign has announced Biden trips to battlegrounds Michigan next Wednesday and Pennsylvania on September 11.

As the Democrat emerges more from his Wilmington, Delaware home, Trump is already barnstorming across battleground states, warning voters that a Biden administration would leave them less safe and repeating his baseless attacks on the integrity of mail-in voting.

In recent weeks Trump has visited Minnesota, Wisconsin, Iowa, Arizona, New Hampshire and North Carolina, with a rally scheduled for Thursday evening in Pennsylvania.

Trump mocked Biden's foray into Wisconsin, pushing a new nickname for the challenger that presumably refers to lower recent profile on the campaign trail.

Until now Biden has hesitated to hit the road, rigorously adhering to local pandemic health guidelines and campaigning through webcasts, advertising and television.

"Joe Hiden' gets off his airplane, grabs and shakes a rather stunned man's hand (like in the old days), then touches his (Joe's) face and mask with the same hand," the president tweeted.

"No crowd, no enthusiasm for Joe today. Law & Order!"

Biden leads Trump in national polling but the gap is closer in swing states including Wisconsin, which Trump narrowly flipped from Democrats in his improbable 2016 election victory.

He is no doubt using security fears to hammer home his law-and-order message.

Demonstrations in Kenosha began peacefully the night Blake was shot, but descended into violence for several nights running.

It culminated August 25 when two people were shot dead. A 17-year-old white Trump supporter has been arrested and charged with murder.

The president has refused to condemn the killings or the growing presence of armed vigilantes at protests, and during his visit he equated the demonstrations demanding racial justice with "domestic terror" by violent mobs.

Community leader Tim Mahone, who moderated the roundtable, applauded Biden for presenting a more optimistic vision.

"We're hurting right now," he told Biden. "Your leadership is important, in Kenosha and in our country."