An altercation on a downtown Minneapolis sidewalk turned deadly Tuesday night when a man in his 30s was shot and killed, according to police.

Minneapolis Police Chief Brian O’Hara said the altercation on the 1500 block of 11th Avenue S. involved people who knew each other and escalated to the point that one person pulled out a gun. The shooting occurred around 6:30 p.m.

“Police officers immediately attempted to provide life-saving first aid, and they were later joined by EMS,” the chief said. “Unfortunately, that male was pronounced deceased at the scene.”

Investigators interviewing witnesses and relatives later on the city block, within view of U.S Bank Stadium and around the corner from a soccer game at a crowded Elliot Park. Video from cameras positioned around the block could offer further evidence, O’Hara added.

O’Hara said he was concerned about the possibility of further violence and retaliation among the people involved in the altercation and that his department was taking swift action to try to prevent that.

The chief said the identity of the victim will be released by the Hennepin County Medical Examiner.