A protester is in a critical condition and on life support after being shot in Charlotte on Wednesday.
It was initially reported that the person had been killed.
"Fatal shot uptown was civilian on civilian," the southern US city said in a statement on Twitter. "@CMPD did not fire shot," it added, referring to the police.
An AFP reporter at the scene of the protests outside the Omni Charlotte hotel saw a man who was apparently shot falling to the ground, bleeding heavily. Witnesses said police brought him into the hotel.
Charlotte Mayor Jennifer Roberts said the victim was taken to the hospital, but did not provide a name or other details.
"It was confirmed not to be a police officer," she told CNN, referring to the shooter. "We're going to continue to try to get more of an update."
The shooting comes as North Carolina Governor Pat Mc Crory declares a state of emergency in Charlotte amid ongoing clashes between protesters and riot police.
Mr Mc Crory said the North Carolina guard and state highway patrol would be deployed to help police.
Some protesters have banged on windows, others have thrown objects at police and stood on cars.
Police fired tear gas, sending demonstrators scattering.
Violence first broke out Tuesday night after police shot to death Keith Lamont Scott, 43, in an apartment complex parking lot earlier in the day.
It was the latest in a series of fatal police shootings of black men that have left the African American community demanding law enforcement reforms and greater accountability.
Keith Lamont Scott, 43, was shot dead in an apartment complex parking lot on Tuesday after an encounter with officers searching for a suspect wanted for arrest.
Authorities said 16 officers and several demonstrators were injured in clashes overnight Tuesday following Scott's death, the latest in a string of police-involved killings of black men that have fueled outrage across the United States.
More protests were expected Wednesday night.
Presidential candidates Donald Trump and Hillary Clinton were quick to weigh in on the violence in Charlotte. It came on the heels of another fatal police shooting of a black man on Friday in Tulsa, with the death of Terence Crutcher captured on video.
"Keith Lamont Scott. Terence Crutcher. Too many others. This has got to end. -H," tweeted Democrat Clinton, signing the post herself.
After calling to "make America safe again" in a tweet, Trump suggested later Wednesday that the Tulsa officer who shot Crutcher had "choked."
"I don't know what she was thinking," the Republican said, speaking at an African-American church in Cleveland, Ohio.
Divergent accounts
The Charlotte shooting took place at 4:00 pm (2000 GMT) Tuesday as officers searching for a suspect arrived in the parking lot of an apartment complex.
They spotted a man with a handgun -- later identified as Scott -- exit and then reenter a vehicle, Charlotte-Mecklenburg police chief Kerr Putney told journalists.
Officers approached the man and loudly commanded him to get out and drop the weapon, at which point Scott exited the vehicle armed, according to police.
"He stepped out, posing a threat to the officers, and officer Brentley Vinson subsequently fired his weapon, striking the subject," the police chief said.
However, Putney added that he did not know whether Scott "definitively pointed the weapon specifically toward an officer."
Carrying a firearm is legal under local "open carry" gun laws.
Scott's relatives told local media that he was waiting for his young son at school bus stop when police arrived. He was not carrying a gun but a book when he was shot dead, they said -- an account police disputed.
"I can tell you a weapon was seized. A hand gun," Putney said. "I can also tell you we did not find a book that has been made reference to."
Protests turn violent
Anger was simmering in Charlotte, especially over the police chief's assertion that Scott had been armed.
"It's a lie," said Taheshia Williams, whose daughter attends school with the victim's son. "They took the book and replaced it with a gun."
On Wednesday afternoon, 100 students, mostly African-American, participated in a "lay-in" protesting police brutality, singing gospel songs.
"I do this for hope," one protester called out. "I do this because I'm tired of being silent," another said.
One man held a sign reading "Legalize being black."
Protests had swelled Tuesday evening as news of the shooting spread, with demonstrators carrying signs that read "Black Lives Matter" and chanting "No justice, no peace!"
Putney said the situation turned violent, with "agitators" damaging police vehicles and throwing rocks at officers.
Riot control police were deployed and used tear gas to disperse the crowd, Putney said.
A group of protesters nevertheless marched to a major highway early Wednesday, shutting down traffic in both directions. They broke into the back of truck and set goods on fire, according to police.
Series of shootings
A string of fatal police shootings -- from Baton Rouge, Louisiana to St. Paul, Minnesota -- has left the African American community demanding law enforcement reforms and greater accountability.
In the southern state of Oklahoma, Tulsa police chief Chuck Jordan called video footage of Crutcher's deadly shooting on Friday disturbing and "very difficult to watch."
The 40-year-old is seen with his hands up, appearing to comply with police officers before he is shot once by officer Betty Shelby and falls to the ground. Another officer fires his stun gun.
The US Department of Justice said Monday it would conduct a federal civil rights probe into the Tulsa shooting, parallel to an investigation being carried out by local authorities.
