A 19-year-old black man who died after being shot by a white police officer in the US was unarmed, officials have said.
The police chief in Madison, Wisconsin, assured protesters over the death of Tony Robinson, that his department would defend their rights to gather while imploring the community to express their anger with "responsibility and restraint".
Mr Robinson died on Friday night in Madison after assaulting officer Matt Kenny, police chief Mike Koval said.
Officer Kenny was injured in the incident, Mr Koval said.
It is unclear if Mr Robinson, who died later in hospital, was alone in the apartment where the shooting took place, Mr Koval said.
But he added of the victim: " He was unarmed. That's going to make this all the more complicated for the investigators, for the public to accept."
Police department spokesman Joel DeSpain said Officer Kenny would not have been wearing a body camera.
Dozens of protesters gathered outside of the Dane County Public Safety Building holding signs that read "Black Lives Matter" - a slogan adopted by activists and protesters around the US after recent officer-involved deaths of unarmed black people - before walking toward the neighbourhood where the shooting took place.
Protesters also shouted the slogan late on Friday night.
Mr Koval, who struck a conciliatory tone during Saturday's news conference, said he understood the anger and distrust taking hold in the community and that "for those who do want to take to the street and protest," his department would be there to "defend, facilitate, foster those First Amendment rights of assembly and freedom of speech".
He also asked protesters to follow what he said was the lead of Mr Robinson's family in asking for "non-destructive" demonstrations.
Officer Kenny has more than 12 years of experience, Mr Koval said, and was involved in a 2007 shooting but was cleared of any wrongdoing because it was a "suicide by cop-type" situation.
The officer has been placed on administrative leave pending the results of this investigation by the state's Division of Criminal Investigation and the Dane County District Attorney's review of that investigation.
A 2014 Wisconsin law requires police departments to have outside agencies probe officer-involved deaths after three high-profile incidents within a decade - including one in Madison - did not result in criminal charges, raising questions from the victims' families about the integrity of the investigations.
The shooting came days after the US justice department cleared Darren Wilson, the white former Ferguson, Missouri, officer who shot and killed 18-year-old Michael Brown, who was black and unarmed, of federal civil rights charges.
A second report found patterns of racial profiling, bigotry and profit-driven law enforcement and court practices in the St Louis suburb.
There have been several high-profile deaths of black suspects killed by police officers in recent months. In New York City, Eric Garner died after officers put him in a chokehold and a video showed him repeatedly saying: "I can't breathe."
A police officer in Cleveland fatally shot 12-year-old Tamir Rice, who had been pointing a pellet gun at a playground. And although Milwaukee police determined the officer who fatally shot Dontre Hamilton acted in self-defence, he was fired for ignoring department policy and treating Hamilton as a criminal by frisking him.
Madison, about 80 miles west of Milwaukee, is the state capital and home to the University of Wisconsin's flagship campus. About 7% of the city's 243,000 residents are black.
Mr Koval said police responded to a call about 6.30pm on Friday of a person jumping into traffic. A second call to police said the man was "responsible for a battery," Mr Koval said.
Officer Kenny went to an apartment and forced his way inside after hearing a disturbance. Mr Koval said the officer was assaulted by Robinson, who then fired at him.
Late on Saturday afternoon, people filled the Fountain of Life Covenant Church for a community meeting. Family members took the stage and read a statement prepared by Mr Robinson's mother, Andrea Irwin.
"I can't even compute what has happened," Ms Irwin's statement said.
"I haven't even had a chance to see his body."
She was not present, and the statement said she was taking time to grieve with her children. Mr Robinson's grandmother, Sharon Irwin, was on the stage as the statement was read, but left immediately after.
Mr Koval, who said he went to Mr Robinson's mother's house overnight and spoke with the 19-year-old's grandparents, expressed his sympathy on Saturday, saying, "19 years old is too young".