A person is on life support after being shot in Charlotte, North Carolina, during the second night of protests against the killing of a black man by police.

The city's police chief had earlier said on Wednesday that he had died of his wound, but officials later said he was in a critical condition.

Charlotte Police Chief Kerr Putney did not identify the person shot or the origin of the gunfire but city officials said on Twitter that the shot was fired by one civilian at another, not by police.

A police officer was also being treated for injuries suffered during the protests, officials added.

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Police in riot gear fired tear gas and rubber bullets to disperse demonstrators after a peaceful rally, which began after the police killing of a black man two days ago, turned violent.

Al Jazeera's Alan Fisher, reporting from Charlotte, said the wounded man was shot in the shoulder.

"Initially it was said he was shot in the head but we saw the injury, it was very much in the shoulder," he said.

"Protesters say police fired the shot. But police say none of their weapons was fired."

Fisher added that protesters were determined to stay in the street even after threats by police that they would be arrested.

"They want to make the point that what happened [Tuesday's police shooting] is unacceptable."

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Earlier, protesters marched towards downtown Charlotte's central intersection. Some confronted a column of patrol cars and officers lining the road about a block from the Omni Charlotte Hotel, and began to surround groups of police and their vehicles.

At that point, police unleashed volleys of rubber bullets, tear gas and flash-bang grenades to disperse the protesters, who began hurling fireworks and debris at officers outside the hotel, Reuters news agency reported.

Keith Lamont Scott, 43, was shot dead in an apartment complex car park on Tuesday after an encounter with officers searching for a suspect wanted for arrest.

The 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 fuelled outrage across the US.

Authorities said 16 officers and several demonstrators were injured in Tuesday's clashes [Jason Miczek/Reuters]

Earlier on Wednesday, presidential candidates Donald Trump and Hillary Clinton weighed in on the violence in Charlotte, which came on the heels of another fatal police shooting of a black man, Terence Crutcher, on Friday in Tulsa.

"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 on 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 on Tuesday as officers searching for a suspect arrived in the car park of an apartment complex.

They spotted a man with a handgun - later identified as Scott - exit and then re-enter a vehicle,  police chief 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 towards 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 handgun," Putney said. "I can also tell you we did not find a book that has been made reference to."

Anger was simmering in Charlotte, especially over the police chief's assertion that Scott had been armed.

"It's a lie," Taheshia Williams, whose daughter attends school with the victim's son. "They took the book and replaced it with a gun."

Series of shootings 

A string of fatal police shootings - from Baton Rouge, Louisiana to St Paul, Minnesota - has left many Americans 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 on Monday it would conduct a federal civil rights probe into the Tulsa shooting, parallel to an investigation being carried out by local authorities.

Source: Al Jazeera News And Agencies