The family of the black man whose shooting death by police in Charlotte, North Carolina, triggered three nights of protests has viewed video of the episode, as pressure is growing for police to make the footage public.

A lawyer for the family of Keith Scott said it was unclear if Scott was holding a gun when killed.

Scott's family called on police to immediately release the two police videos that they saw on Thursday.

Scott, 43, was killed on Tuesday by a black police officer as part of a police search for another man. Police contend Scott was carrying a gun when he approached officers and ignored repeated orders to drop it. His family previously said he was holding a book, not a firearm.

Charlotte-Mecklenberg police Chief Kerr Putney told reporters that he is not going to do make the video public because he does not want to jeopardise the investigation.

Scott's death is the latest to stir passions in the United States over the police use of deadly force against black men.

The family's viewing of the video came on the same day that a white police officer in Tulsa, Oklahoma, was charged with first-degree manslaughter in the fatal shooting of an unarmed black man whose car had broken down and blocked a road.

In Charlotte, Scott's family said it still had "more questions than answers" after watching two police body camera videos of the officer shooting him dead in the parking lot of an apartment complex.

"While police did give him several commands, he did not aggressively approach them or raise his hands at members of law enforcement at any time," Justin Bamberg, an attorney for the family, said in the statement.

"It is impossible to discern from the videos what, if anything, Mr Scott is holding in his hands," the statement said, adding that Scott's hands were by his sides and he was slowly walking backward.

Scott's killing prompted two nights of riots in Charlotte. Residents marched again on Thursday night in a peaceful protest.

Source: Agencies