CHICAGO • A violent clash broke out in Chicago's predominately black South Side neighbourhood after police shot and killed a man whom they suspected was carrying a firearm.

A crowd of about 150 residents shouted "murderers" and obscenities during a protest last Saturday, local media reports said. They tossed rocks, bottles and jumped on police cars near the crime scene in the 2000 block of 71st Street.

Officers armed with batons squared off with the protesters, with punches thrown on both sides, multiple media accounts said and videos posted on Twitter show. Officials said three or four officers suffered minor injuries and one patrol car was damaged. Four protesters were arrested.

Few details of the shooting were available other than a police statement which said that at about 5.30pm, foot patrol officers saw a man "exhibiting the characteristics of an armed person".

Chicago police patrol chief Fred Waller told the New York Times and other media that officers saw a bulge in his trousers that they believed to be a gun. Upon approaching him, "he started flailing and swinging away, trying to make an escape" and "reached for the gun".

The official statement from the Chicago police said "an armed confrontation ensued, resulting in an officer discharging his weapon and fatally striking the offender", adding that they recovered a "gun and two ammunition magazines" at the scene.

A crowd gathered after the shooting and rumours that the man was unarmed incited the crowd, police spokesman Anthony Guglielmi told the Chicago Tribune.

The protest ended at about 10.30pm and the officer involved will be placed on desk duty while the incident is investigated, officials said.

REUTERS