There have been violent clashes between police and protesters in the US city of Minneapolis following the death of an unarmed black man in police custody.

Police fired tear gas and protesters threw rocks and sprayed graffiti on police cars.

Video of the death shows George Floyd, 46, groaning “I can’t breathe” as a policeman kneels on his neck.

Four police officers have been fired, with the mayor saying that being black “should not be a death sentence”.

The incident echoes the case of Eric Garner, who was placed in a police chokehold in New York.

His death became a rallying call against police brutality and was a driving force in the Black Lives Matter movement.