WASHINGTON — Hundreds of protesters took to the streets and bands of looters broke into businesses for a second night on Tuesday after officers in Philadelphia shot and killed a Black man who was holding a knife in an encounter that city officials say raises questions.

Following a smaller protest that turned destructive on Monday, Pennsylvania Gov. Tom Wolf on Tuesday authorized the state’s National Guard to deploy to help police protect property and quell unrest in the state’s largest city.

Monday’s demonstrations and looting left shops damaged and at least 30 officers injured, including one hospitalized with a broken leg after being struck by a truck.

On Tuesday, police and protesters clashed again, but officers took a more aggressive tack, filling the streets with lines of riot police who stopped marchers and made several arrests earlier in the evening.

Overnight into early Wednesday morning, police continued reporting sporadic incidents but most of the crowds had dispersed.

The latest shooting of the 27-year-old man caught on cell phone video, draws fresh attention to fatal use of force by police following months of protests over how officers treat Black people. The shooting and violent protests — which left 30 officers injured — also sharpen the focus on the swing state of Pennsylvania a week before the presidential election.

Speaking at a campaign rally in Wisconsin on Tuesday, President Donald Trump attempted to tie the protesters to his democratic rival, former Vice President Joe Biden, without providing evidence of a link.

"Last night (Monday) Philadelphia was torn up by Biden-supporting radicals," he said. "Thirty police officers, Philadelphia police officers, they were injured, some badly. Biden stands with the rioters, and I stand with the heroes of law enforcement."

In a joint statement, Biden and his running mate, Kamala Harris, said: "We cannot accept that in this country a mental health crisis ends in death.

"It makes the shock and grief and violence of Monday's shooting that much more painful, especially for a community that has already endured so much trauma," they added while condemning Monday's looting, calling it a crime. — Agencies