Four young men were charged in the shooting of 13 people at a park in President Barack Obama's adopted hometown Chicago which has been struggling to stem violent crime, police said Tuesday.
The gang-related shooting has renewed calls for stricter gun controls after an assault rifle was used to spray bullets at a crowd gathered for a pickup basketball game.
A toddler who was shot in the ear was among those wounded Thursday night in the city's troubled South Side.
"Not only do we believe a military-grade weapon was used in this shooting, but one of the offenders charged last night was convicted of aggravated unlawful use of a weapon/possession of a firearm by a felon a little more than a year ago," Police Superintendent Garry McCarthy said.
"He received boot camp for that gun crime and was back out on the streets to be a part of this senseless shooting. That is unacceptable."
The only way the city will ever be able to "truly address violence for the long-term" is with the support of state and federal laws that keep illegal guns off the street and provide "real punishment" for criminals who use them, McCarthy said.
Mayor Rahm Emanuel praised the "great police work" which led to swift arrests and also called for tougher gun laws.
"As we invest heavily in programs for youth, in new policing strategies, and in building supports for those most likely to fall into gangs, we also need a three-year mandatory minimum bill for gun crimes," he said in a statement.
The shooting came as Chicago struggles to stem an epidemic of gang violence that helped push the city's murder toll up 16 percent last year, with 506 people killed.
Gun violence has continued at a slower but still-brisk pace this year despite a major police crackdown.
The number of murders is down 20 percent at 306 so far this year while the number of shootings is down 22 percent at a whopping 1,402 incidents, the latest crime report showed.
Obama returned to his adopted hometown earlier this year to appeal for an end to the "senseless" gun violence ravaging Chicago as he pressed for ambitious gun control measures, which so far have been stalled in the US Congress.
Charged in Thursday's shooting were: Tabari Young, 22, who police said fired the "military-grade weapon"; Bryon Champ, 21, who also fired a gun in the shooting; Kewane Gatewood, 20, who supplied the assault rifle; Brad Jett, 22, a "documented gang member" who acted as a lookout and was recently released from prison on gun charges.
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