Hundreds of protesters marched through the US city of Philadelphia for a second night, demanding racial justice after police fatally shot a black man.
The family of Walter Wallace, 27, say he was suffering a mental health crisis when officers opened fire on him.
Police say they shot him because he would not drop a knife he was holding.
Police reinforcements as well as the National Guard have been deployed. Authorities say 30 officers were hurt during the first night of clashes.
The city’s police have also accused protesters of looting and ransacking businesses during the unrest, which started on Monday.
Mr Wallace had bipolar disorder, and his wife told officers this before they shot him, a lawyer representing his family said.
Philadelphia also saw large protests earlier this year over police brutality and racism following the death of George Floyd in Minnesota.
What’s the situation in Philadelphia?
On Tuesday night, the marches began peacefully but became more confrontational as the evening drew on.
Officers in riot gear arrived in squad cars, on bicycles and on buses, and used their bikes to shove protesters back from barricade lines.
Police warned residents to stay away from the riverfront Port Richmond district as widespread looting occurred.
The Philadelphia Office of Emergency Management advised residents across a swathe of the city to stay indoors because of “widespread demonstrations that [had] turned violent with looting”.
According to the Philadelphia Inquirer, protesters tried to erect makeshift barricades using bins. Police used pepper spray and batons after saying they were attacked by demonstrators.
Shops around the city closed early and set up barricades on Tuesday. Residents found pharmacies shuttered and were unable to get medicine, according to CBS News.
On Monday, more than 300 people took to the streets to protest, and 91 were arrested. One officer was in hospital with a broken leg and other injuries after being struck by a pickup truck.
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, Mr 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 yesterday’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.
Philadelphia is the largest city in Pennsylvania, a state critical to next week’s presidential election.
What have city officials been saying?
Mayor Jim Kenney, a Democrat, said the video of Monday’s fatal police shooting presented “difficult questions that must be answered”.
The mayor said he was looking forward “to a speedy and transparent resolution for the sake of Mr Wallace, his family, the officers, and for Philadelphia”.
Philadelphia Police Commissioner Danielle Outlaw said she had visited the scene and felt the “anger of the community”.
“We anticipate the chance of additional incidents of civil unrest,” she said at a news conference earlier. “And as such, we will be taking additional steps to ensure order. We will increase our officer presence around the city at key locations.”
What do we know about the shooting?
Police said it happened at about 16:00 (20:00 GMT) on Monday, when two officers responded to a report of a man with a weapon in the neighbourhood of Cobbs Creek in West Philadelphia.
Police spokeswoman Tanya Little told AP news agency that a man, later identified as Mr Wallace, was holding a knife when the officers approached, and instead of following orders to drop the weapon he “advanced towards them”.
Both officers fired “several times”, hitting Mr Wallace in the shoulder and chest, she said. One of the officers drove him to a hospital, where he was pronounced dead, according to Ms Little.
Footage shared on social media shows two officers pointing their guns at Mr Wallace as he walks towards them. The officers back away from him and shout at him to put the knife down.
Shots are then fired and Mr Wallace is seen lying on the street.
Mr Wallace’s father told the Philadelphia Inquirer that his son had mental health issues and was on medication. “Why didn’t they use a Taser?” he asked.
At Tuesday’s news conference, officials said the officers both fired seven shots each. The officers, who have not been named, were wearing body cameras and did not carry tasers.
Meanwhile, Mr Wallace’s family lawyer said they had called for an ambulance – not police – to help deal with Walter Wallace’s mental issues.
Instead, two police officers arrived, lawyer Shaka Johnson was quoted as saying by the Inquirer. Mr Wallace’s pregnant wife told them her husband had bipolar disorder and was in crisis.