The afternoon shooting happened near King Park, according to information provided by the Milwaukee County medical examiner, reported NBC News.

Police said the incident was not related to the convention.

Police did not provide the identity of the man who was killed in the incident.

Milwaukee Police Chief Jeffrey B. Norman told NBC News 13 Columbus bicycle officers assigned to cover daily events associated with the convention happened to be in the neighbourhood on Tuesday, discussing the day's security plans.

Shortly after 1 p.m., a confrontation erupted between two men, one with a knife in each hand, the other unarmed, near the Columbus officers, the chief said at an evening news conference.

The officers rushed to intervene and, after the armed man allegedly failed to comply with orders to drop the knives and then charged at the other man, a number of them opened fire, Norman said.

No officer was injured in the incident.