CHICAGO - Thirteen people have been shot at a park on Chicago's southwest side, including a 3-year-old boy who was in critical condition.

Officer Amina Greer said the shooting occurred shortly after 10 pm Thursday.

Police investigate the scene of a shooting that injured at least 13 people, including a three-year-old boy, at Cornell Square Park in Chicago on Thursday night. [Photo/Xinhua]

A witness, Julian Harris, told the Chicago Sun-Times that dreadlocked men fired at him from a gray sedan before turning toward Cornell Square Park in Chicago's Back of the Yards neighborhood and firing at people. He said his 3-year-old nephew was wounded in the cheek.

"They hit the light pole next to me, but I ducked down and ran into the house," Harris said. "They've been coming round here looking for people to shoot every night, just gang-banging stuff. It's what they do."

Chicago Fire Department officials said the child was in critical condition. Two other victims were also in critical condition. The others were reported in serious to fair condition.

Greer told The Associated Press early Friday that police have since identified a 13th victim, a 33-year-old woman with a gunshot wound to the back near one shoulder. She added that no arrests have been made and she had no further information to give out at the time.

"It's an ongoing investigation," Greer added.

The shooting comes nearly three weeks after Chicago saw an outburst of violence over the Labor Day weekend that ended with eight dead and 20 others injured. The city's Police Department has responded to shootings that have grabbed national headlines by stepping up its crime-fighting efforts, paying overtime to add patrols to some neighborhoods, including the Back of the Yards, where Thursday's shooting took place.

According to Greer, at least 10 ambulances responded to the scene, transporting victims to several area hospitals. One victim transported himself to a hospital, police said.

Police spokesman Ron Gaines said victims were being interviewed to determine the circumstances of the shooting. He said no one had been taken into custody.

Francis John, 70, said she was in her apartment when the shooting occurred. She said she went down to see what was going on and "a lot of youngsters were running scared." A 30-year resident, she said she was surprised by what had happened.

She told the Sun-Times there hasn't been much gun violence in the neighborhood in recent years, adding the neighborhood went from good to bad 10 years ago, to better recently.