Violent protesters rampaged through parts of downtown Charlotte on Thursday as anger continued to build over the deadly police shooting of an African American.

North Carolina state governor Pat McCrory declared a state of emergency for the state’s largest city and called in the National Guard after Charlotte’s police chief said he needed help.

Violence erupted for a second night after Keith Lamont Scott was shot dead by a black officer on Tuesday.

Meantime on Friday morning (AEST), a Tulsa police officer who shot dead an unarmed black man last Saturday was charged with manslaughter, threatening to heighten tensions in the United States again.

Earlier in Charlotte, a peaceful prayer vigil turned into an angry march and then a night of violence and a protester was shot and critically wounded, while police in riot gear were charged while trying to protect an upscale hotel in the city’s downtown area.

City officials initially said the protester was shot by another civilian, and not police, but now the Charlotte–Mecklenburg Chief of Police Kerr Putney has acknowledged that is still under investigation after claims an officer pulled the trigger.

The protester has since died in hospital, police told CNN. The victim was identified as Justin Carr, 26, from Charlotte.

At least nine people have been injured and 44 arrested, the charges including looting and assault.

On Wednesday, hundreds of protesters shouted “black lives matter” and “hands up, don’t shoot” as police fired flash grenades and tear gas to disperse them.

A man tries to rile up the crowd. Photo: AP

Several groups of a dozen or more protesters stayed behind attacking people – including reporters – shattering windows to hotels, office buildings and restaurants, and setting small fires.

At one point, television news helicopters showed protesters on the loop highway around the CBD trying to stop cars for several minutes before police arrived.

“My heart bleeds for what our great city is going through,” Governor McCrory said on WBTV-TV.

North Carolina governor Pat McCrory declared a state of emergency after protesters took to the streets of Charlotte. Photo: AP

Authorities said three people and four police officers have been injured during the protests.

The violence occurred amid questions over what took place Tuesday afternoon when 43-year-old Mr Scott was shot and killed in the parking lot of his apartment complex.

Police did not release camera footage from the vehicle which attended the scene, but said Scott had a gun and refused several orders to drop his weapon. Scott’s family and neighbours said he was holding a book.

Protesters confront bicycle officers as anger built in the city. Photo: AP

“He got out of his car, he walked back to comply, and all his compliance did was get him murdered,” said Taheshia Williams, whose balcony overlooks the shady parking spot where Scott sat Tuesday afternoon.

Chief Putney was angered by the stories on social media, especially a profanity-laced, hour-long video on Facebook, in which a woman identifying herself as Scott’s daughter screamed “My daddy is dead!” at officers at the shooting scene and repeating that he was only holding a book.

Watch the video below (Warning: contains strong language)

https://www.youtube.com/watch?v=nHR9XMYHpJ8

Mr Putney was adamant that Scott posed a threat, even if he didn’t point his weapon at officers, and said a gun was found next to the dead man.

“I can tell you we did not find a book,” he said.

Not long after the Facebook video was posted Tuesday night, the first night of destructive protests began near the scene of the shooting, about 15 miles northeast of downtown Charlotte.

Dozens of demonstrators threw rocks at police and reporters, damaged squad cars, closed part of Interstate 85, and looted a stopped truck and set a fire. Authorities used tear gas to break up the protests.

The distrust of police continued after Wednesday’s shooting of a protester, with many demonstrators maintaining he was shot by police.

A woman displays her hands during a rally/prayer vigil at Marshall Park in Charlotte. Photo: AP

“We protesting. Why the hell would we target each other?” protester Dino Davis said.

“They say it was the tear gas, and it looked like one of the tear gas [canisters] exploded. But I think it was a rubber bullet because some of those rubber bullets can penetrate.”

Calls for police to release the video increased. North Carolina has a law that takes effect October 1 requiring a judge to approve releasing police video, and Putney said he doesn’t release video when a criminal investigation is ongoing.

After about four hours, the violence began winding down. Hotel employees and security guards immediately started cleaning up broken glass.

Bank of America told its thousands of employees working in its 60-story skyscraper to stay home on Thursday.