The killing of George Floyd by a white police officer polarised the country politically and racially in the middle of a presidential campaign and as states begin to ease lockdowns imposed during the Covid-19 pandemic.

Protests are continuing in cities across the US on Tuesday, following the death of George Floyd, who died after a white Minneapolis police officer pinned him down and pressed his neck with his knee as the man pleaded that he couldn’t breathe.

Demonstrators set fire to a strip mall in Los Angeles, looted stores in New York City and clashed with police in St Louis, Missouri, where four officers were taken to hospital with non-life-threatening injuries.

At least five US police were hit by gunfire during violent protests.

It is the most widespread unrest in the US since 1968, when cities went up in flames over the slaying of civil rights leader Martin Luther King Jr.

US President Donald Trump vowed on Monday to order a military crackdown on the protests, saying he was sending thousands of troops onto the streets of the capital.

Police in Las Vegas said on Monday that 338 people were arrested during three nights of protests.