A video of the horrifying incident has been shared widely on social media.
Four policeman in Minneapolis, Minnesota have been fired following the killing of George Floyd, an unarmed black man. Video footage of the incident suggests that at least one officer pressed his knee into Floyd's neck for several minutes, while Floyd said "I can't breathe" and "Don't kill me".
The video also captures the voices of onlookers repeatedly asking the police officer to stop.
Mayor of Minneapolis Jacob Frey has confirmed that all four responding officers have been terminated from their posts, tweeting: "Four responding MPD officers involved in the death of George Floyd have been terminated. This is the right call."
Elsewhere, Frey said of one of the officers involved: "This officer failed in the most basic, human sense."
Demonstrations have begun in the city, as protestors demand that charges be brought against the police officers involved.
The protestors in Minneapolis have since been met with police in riot gear, who have also used tear gas to disperse the crowds.
The case is another high profile example of an unarmed black person dying at the hands of police in the United States.
It comes weeks after a video was released showing the death in Georgia of
Ahmaud Arbery, an unarmed black man, while he was jogging.
