CHICAGO An apparently gang-related shooting spree on Chicago's South Side left 13 people wounded, including a 3-year-old child, police said on Friday.
Chicago has been struggling with gun violence for years, which hurt the city's reputation and put pressure for change on Mayor Rahm Emanuel.
"I can tell you that it's an ongoing investigation," Chicago Police Department spokeswoman Amina Greer said on Friday.
No arrests have been made so far, Greer said, adding that police believe the motive for the shooting was gang-related.
According to witnesses, gunfire rang out late Thursday as gunmen sprayed a basketball court with bullets in a park in the city's Ninth District.
"We were sitting in the park talking, then two dudes came up, stood by the gate for a minute, then they just started shooting," said Michelle Adams, 16.
Other witnesses said the gunmen had driven up and fired on the basketball court from their vehicle.
Mayor Emanuel cancelled two meetings in Washington on opportunities for Chicago and was headed back to his city after being notified about the shooting, his press office said.
"Senseless and brazen acts of violence have no place in Chicago and betray all that we stand for," Emanuel said in a statement. "The perpetrators of this crime will be brought to justice and prosecuted to the full extent of the law."
Police said that besides 3-year-old Deonta Howard, those injured ranged in age from 15 to 41.
As of Friday morning, three of the gunshot victims, including Howard, were in serious to critical condition in area hospitals.
Howard was in surgery, said Naphtali Dukes, 38, who said he was the boy's cousin.
"They said he's going to make it," Dukes said.
Mitchell Gary, 53, said his brother was shot in the back and buttocks and his nephew was shot in the arm and ankle.
Gun violence in Chicago led to more than 500 murders in 2012, according to a report this week by the FBI.
By comparison, New York City, with a population three times Chicago's, had 419 murders in 2012, the FBI said.
So far this year, the city's murder rate is down 22 percent from a year earlier. Chicago Police Superintendent Garry McCarthy has said recently that murders were down 45 percent in 20 neighbourhoods targeted since February for additional police, including expanded use of foot patrols.
One Chicago murder this year that caught national attention was of Hadiya Pendleton, 15, an honour student killed at a park just days after she performed at a January presidential inauguration event in Washington.
Other notorious Chicago killings include the death of a 7-year-old girl last summer at her mother's candy stand and the shooting of a 6-month-old baby last March by a gang member who was aiming at her father.
Chicago's crime problem is just one of a host of issues plaguing Emanuel. The former White House chief of staff under President Barack Obama pledged to clean up the streets of the city after a successful, well-financed run for office in 2011.
Citing budget problems, the city closed 50 public schools in May, angering parents and the powerful teachers union. The city faces large and growing pension liabilities, and Emanuel's former comptroller was recently indicted in Ohio.