Charlotte protests: The two images that sum up what is happening in North Carolina

A man has been shot and a state of emergency declared in the North Carolina town of Charlotte, after a second night of violent protests shook normally quiet town, known as the banking capital of the South.

Dramatic images showed Charlotte police lined up in full riot gear after a peaceful prayer vigil turned into an angry march and a night of unrest.

And at the height of the clashes, a man was shot outside a hotel in what police described as a "civilian on civilian" incident. Initially, the man was reported as dead, but he is now understood to be in a critical condition in hospital.

In the wake of the shooting, many protesters chanting "black lives matter" and "hands up don't shoot" were dispersed by police using tear gas and flash grenades.

But Charlotte's police chief said the force was unable to cope on its own, after 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 downtown, trying to stop cars for several minutes before police arrived.

Authorities said three people and four police officers were injured, but those figures had not been updated early Thursday morning. Videos and pictures on Twitter showed reporters and other people being attacked.

The unrest took many by surprise in Charlotte, the banking capital of the South with a population of 830,000 people, about 35 percent of them black. The city managed to pull through a racially charged shooting three years ago without the unrest that erupted in recent years in places such as Baltimore, Milwaukee and Ferguson, Missouri.

"My heart bleeds for what our great city is going through," North Carolina Gov. Pat McCrory said on WBTV-TV. He was mayor of Charlotte for 14 years before becoming governor.

The unrest started amid questions about what happened Tuesday afternoon when 43-year-old Keith Lamont Scott was shot and killed in the parking lot of his condominium complex. Police did not release dashboard or body camera footage, but said Scott had a gun and refused several orders to drop his weapon. Scott's family and neighbors said he was holding a book.

"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 was Tuesday afternoon. She said he often waited there for his son because a bicycle accident several years ago left him stuttering and susceptible to seizures if he stayed out in the hot sun too long.

Charlotte Police Chief Kerr Putney was angered by the stories on social media, especially a profanity-laced, hourlong video on Facebook, where 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.

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," the chief said.

Not long after the Facebook video was posted Tuesday night, the first night of destructive protests began near the shooting scene, 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. Many demonstrators didn't believe officers weren't the ones who shot the protester.

"We protesting. Why the hell would we target each other?" Dino Davis said. "They say it was the tear gas, and it looked like one the tear gas exploded. But I think it was a rubber bullet because some of those rubber bullets can penetrate."

Calls for police to release the dashboard and body-cam video of the Keith Lamont Scott incident have increased.

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

But that video may be the only thing that calms Charlotte, said John Barnett, who runs a civil rights group called True Healing Under God, or THUG.

"Just telling us this is still under investigation is not good enough for the windows of the Wal-Mart," he said.

Additional reporting by agencies