US Election 2020: Donald Trump and Joe Biden condemn looting amid protests over shooting of Walter Wallace

Joe Biden and Donald Trump have unleashed attacks on each other like never before - both trying to capitalise on the shooting in Philadelphia, which saw a second successive night of violence there.

Rioters and looters have taken to the streets of Philadelphia after the police shooting of a Black man.

Walter Wallace, 27, was holding a knife on Monday afternoon when police fired 14 rounds, killing him.

Wallace's own parents had called the police - crying out for help - as their son, who was having mental problems was carrying a knife.

For a second night running, Philadelphia saw outrage - people angry that another Black life seemed not to matter.

On Wednesday (local time) Trump blamed the Democrats for failing to act tough, while Biden called the President's way, "reckless".

Trump downplayed the shooting and focussed his attention on the protest.

"It's a terrible thing, what -- what I'm witnessing is terrible, and frankly that the Mayor or whoever it is that's allowing people to riot and loot and not stop them is also just a horrible thing," he said.

"But they should bring in their National Guard if the police need help and they should do something. You can't let that go on. Again, a Democrat-run state, a Democrat-run city."

Biden, who has been accused by Republicans for being soft on crime, said there's no excuse for the looting.

"There are certain things we're going to have to do as we move along. And that is how we deal with how you diminish the prospect of lethal shooting in circumstances like the one we saw," he said.

"But there's no excuse for the looting."

Skillz the Barber in Philadelphia questions whether a "President Joe" can truly fix the racial division.

"We hope he does a good job, learns something from [Barack] Obama, but we just don't know," he said.

"I don't know who is good or bad for the job - I just know something has to change."