'I can't breathe' protests heat up as curfews imposed in US cities

Civil unrest flared and curfews were imposed in several major US cities as demonstrators took to the streets to vent outrage at the death of a black man shown on video gasping for breath as a white Minneapolis policeman knelt on his neck.From Los Angeles to Miami to Chicago, protests marked by chants of "I can't breathe" - a rallying cry echoing the dying words of - began peacefully before turning unruly as demonstrators blocked traffic, set fires and clashed with riot police, some firing tear gas and plastic bullets in an effort to restore order.