Chicago authorities say 13 people, including a 3-year-old child, were injured by a shooting in a park located in the US city's Back of the Yards neighbourhood.

Chicago Fire Department officials told Al Jazeera that the child was in a critical condition. Two adult victims were also in critical condition, officials said. Officer Amina Greer told the AP news agency that the shooting happened shortly after 10pm on Thursday.

There were no immediate reports of fatalities, Greer said, and no one was in custody.

According to Greer, at least 10 ambulances responded to the scene, taking the victims to several different hospitals.

A witness, Julian Harris, told the Chicago Sun-Times newspaper that men fired at him from a grey car before turning towards Cornell Square Park and firing at people in the area. He said his 3-year-old nephew was wounded in the cheek.

Chicago has been torn by gun violence in recent years, racking up more than 500 murders in 2012, according to a report this week by the FBI.

By comparison, New York City, which has a population three times the size of Chicago, recording 419 murders in 2012, the FBI said. 

The Chicago Tribune newspaper's blog reported that the shootings appeared to have taken place at a basketball court. Injured people, the newspaper said, were being carried out of the park on stretchers.

Source: Al Jazeera and agencies