Thirteen people were wounded in a shooting at a party on Chicago's south side intended to honour the victim of an earlier shooting, police said, adding that they have taken into custody two people they consider of interest to the investigation.
It was the latest in a string in violent crimes in Chicago, where the number of murders reported annually remains higher than the combined figure from New York and Los Angeles, two much larger cities.
The victims ranged in age from 16 to 48, and 12 were in local hospitals on Sunday, hours after police responded at the scene at around 12:30 am local time, according to a police statement.
Four of the victims, including a 16-year-old male, were critically wounded on Sunday afternoon after suffering gunshot wounds to the chest or lower back.
The police statement said one of the people of interest, a 25-year-old male, was also a victim in the shooting.
Police did not immediately respond to a request for further details.
"This party was given in the memorial of a subject that was slain in April," said Chicago Police Chief of Patrol Fred Waller. "We're still developing details as far as that goes," he said.
The city is in the midst of a search for a new permanent police superintendent, after Mayor Lori Lightfoot fired Eddie Johnson weeks before he was due to retire, accusing him of lying to her over an October incident where patrol officers found him asleep in his car.