Police officers have been accused of "brutality" after a shocking video emerged of a man in his underwear being tackled to the ground and "punched in the face."

An onlooker and her family were waiting for a table outside a restaurant in Charlotte, North Carolina on Saturday, September 14, when she witnesses the troubling encounter.

A video shows the man in his underwear and sunglasses standing on the sidewalk - before he is tackled from behind by a cop.

Two more officers join in "repeatedly punching" the man "in the face and kneeing" him.