Police officers investigate a crime scene in Chicago. Picture used for illustrative purposes only. File/AP

Eight people were shot including a young girl who was killed in what Chicago police believe was gang-related violence on the city's South Side on Saturday night.

The 7-year-old girl was shot in the head and died, while a 1-year-old boy and a 7-year-old boy were each shot multiple times and listed in critical condition, Chicago Police Department Deputy Chief Don Jerome said in a news briefing at the scene on a block of 52nd Street near Damen Avenue.

Police responding to a gunfire alert around 9pm applied tourniquets and chest seals to victims, who also included adults between the ages of 19 and 40, Jerome said.

The victims, who were standing outside at a family gathering at the time of the shooting, were transported to area hospitals by the Chicago Fire Department.

The investigation was still in the preliminary stages but witness accounts described two possible shooters on foot, Jerome said.

"This was not a random act of violence. It was likely gang-related,” Jerome said. "Regardless of the motivation for this incident, three innocent children were struck tonight and one of them tragically succumbed to her wounds. The offenders' actions, make no mistake, are horrific and unnaceptable in our city.”

Associated Press