Four people, including the alleged shooter, have been charged in the shooting at a Chicago park that left 13 people wounded, police said Tuesday.

"As of right now we have four offenders charged in this shooting, including the man who fired that military grade weapon and the man who supplied that military grade weapon," police superintendent Garry McCarthy said during a press conference.

He identified the men facing charges of attempted murder and aggravated battery with a firearm as Tabari Young, 22, Bryon Champ, 21, Brad Jett, 22, and Kewane Gatewood, 20.

Young, who has around 10 previous criminal violations, was named as the one who fired shots from a military assault rifle last Thursday night at Cornell Square Park.

Champ, an ex-convict and gang member, also opened fire at the crowd, according to police, while Gatewood was named as the person who supplied the assault rifle.

"Illegal guns and weapons designed for war do not belong on the streets of Chicago," McCarthy said, repeating his call for stricter gun-control laws.

All of the accused belonged to the Black P. Stones gang and the shooting was said to have been in revenge against members of the Gangster Disciples who were at the park because a few hours earlier Champ had been grazed by a bullet in a confrontation with them.

Police said that at the shooting scene they collected 16 spent shells of the kind normally used in AK-47 assault rifles, a weapon that has not been common among the gangs operating on Chicago's South Side.

Of the 13 wounded, all of them African Americans, Deonta Howard, a 3-year-old boy, is recovering from two operations to repair the damage from a bullet that hit him in the face and he will later need plastic surgery, doctors said. EFE