Major businesses have told their employees not to report to work in Charlotte, North Carolina, after a second night of violence surrounding the police shooting of Keith Scott.

As North Carolina governor Pat McCrory declared a state of emergency and the National Guard streamed into Charlotte around 4am Thursday to help control protests, uptown corporations including Bank of America, Wells Fargo, Fifth Third Bank, United Way and Duke Energy asked employees to stay at home.

"Due to the recent events and the declared state of emergency in Charlotte, Wells Fargo team members are not required to report to work Thursday, September 22," an email from Wells Fargo read.

The Mint Museum, the uptown Epicenter and certain public transport lines are also closed on Thursday.

The advice to employees comes as protesters on Wednesday night and early Thursday morning were dispersed by police with flashbangs, tear gas and bullets - one man was critically injured and is on life support.

Police said they were not responsible for the injury and were trying to break up inter-protester violence.

The major unrest comes after several police shootings of black peopleover the last week, including 13-year-old Tyree King who was carrying a BB stun gun in Columbus, Ohio, an unarmed 43-year-old called Terence Crutcher in Tulsa, Oklahoma, who was holding his hands above his head and then, in North Carolina, Keith Scott, a father to seven children who was reportedly sitting in his car, reading a book.

Man shot at Charlotte protest in North Carolina

Police have disputed claims that Scott was unarmed, and said they had found a gun at the scene, not a book.

They have yet to release police dashcam footage, citing a law that the videos are not a public record and can only be released with a court order.

That law does not come into effect until 1 October, according to the American Civil Liberties Union.

Todd Walther, spokesman of Charlotte fraternal order of police, told CNN that the protesters are out-of-town criminals who are “stealing” from shops and are not helping the cause.

"These are not protesters," he said. "These are criminals that are doing this violence."

Mr Walther said he had seen the dash cam footage and insisted that Scott was armed, ignored repeated calls to drop his weapon upon exiting his car, and that the officers surrounding him were clearly identifiable by a vest or jacket, rebutting claims they were in plain clothes.

"There’s no mistaking these were officers," he said.

Charlotte mayor, Jennifer Roberts, pleaded for transparency on Wednesday.