Violence has erupted in cities across the US on the sixth night of protests sparked by the death in police custody of African-American George Floyd. Dozens of cities imposed curfews, but many people ignored them, leading to stand-offs and clashes. Riot police faced off with protesters in New York, Chicago, Philadelphia and LA, firing tear gas and pepper bullets to try to disperse crowds. Police vehicles were set on fire and shops were looted in several cities. The country is experiencing the most widespread racial turbulence and civil unrest since the backlash to the assassination of Martin Luther King in 1968. The outpouring of anger began last Tuesday, after a video showed Mr Floyd being arrested in Minneapolis and a white police officer continuing to kneel on his neck even after he pleaded he could not breathe and fell unconscious. More than 75 cities have seen protests, with streets only days ago deserted because of coronavirus full of demonstrators marching shoulder to shoulder. Some US officials have warned of protest-connected virus outbreaks. The Floyd case has reignited deep-seated anger over police killings of black Americans and racism. It follows the high-profile cases of Michael Brown in Ferguson, Eric Garner in New York and others that have driven the Black Lives Matter movement. For many, the outrage also reflects years of frustration over socio-economic inequality and discrimination, not least in Minneapolis itself, where George Floyd died.