A crowd of about 150 people shouted "murderers", threw objects and jumped on police cars during the confrontation in Chicago's South Side area, BBC reported.
Officers armed with batons traded punches with the protesters, local media reports said. Three officers sustained minor injuries and there were four arrests.
A string of police killings of black men, some unarmed, has caused outrage and led to protests in cities across the US, the report said.
The dead man's identity has not yet been released but he was thought to be aged in his 30s.
A police statement said officers on patrol in the South Shore district saw the man "exhibiting the characteristics of an armed person".
"An armed confrontation ensued resulting in an officer discharging his weapon and fatally striking the offender," the statement said, adding that police recovered a gun and two ammunition magazines at the scene.
(This story has not been edited by Social News XYZ staff and is auto-generated from a syndicated feed.)
