CHICAGO A series of gun attacks overnight in Chicago left four men dead, following a shooting at a South Side park that wounded 13 people this week, police said on Saturday.
The latest violence came as the city struggled to respond to a rash of street violence.
Chicago Mayor Rahm Emanuel returned home from Washington, after cancelling meetings there, and spoke at a prayer vigil on Friday night where he urged witnesses to Thursday's park shooting to come forward.
"We cannot allow children in the city of Chicago and we will not allow children in the city of Chicago to have their youthfulness, their optimism, their hope taken from them," he said at the vigil. "That's what gun violence does."
Chicago has one of the worst homicide rates in the country, with more violent crime than such places as New York and Los Angeles. The city's police department had been claiming success in stemming the violence with a strategy of flooding 20 high-crime neighborhoods with officers.
The four men killed overnight were shot in separate incidents between 6:15 p.m. on Friday and 3 a.m. on Saturday, said Chicago Police Department spokesman Officer Mike Sullivan.
The victims ranged in age from 18 to 37. Three of the attacks occurred in the city's largely poor South Side, where Thursday night's shootings by suspected gang members carrying an assault weapon took place.
On Friday afternoon, a teenage boy was found shot and killed in the Park Manor neighborhood, police said.
Among the 13 people wounded at Cornell Square Park on Thursday in the Back of the Yards neighborhood was a 3-year-old boy, identified by his family as Deonta Howard, critically wounded when a bullet entered his ear.
The boy's grandmother, 39-year-old Semecha Nunn, said on Friday he was at the park with his mother.
"I know my grandson wasn't the target, he just was in the wrong place at the wrong time," she said.
"But if you have any type of sympathy or a heart, you'll turn yourself in," she added, in a message to the shooters.
Nunn, whose oldest son was shot to death less than a month ago and whose fiance also was wounded in the park, said the violence had to stop.
"I just buried my oldest son, and then to come home to this, yeah, it's scary," she said. "I don't feel safe. It's just sad."
Police say three gunmen were involved in Thursday's attack, which took place on a warm night after residents had watched a basketball game.
None of those shot on Thursday had life-threatening wounds, said Chicago Police Superintendent Garry McCarthy.
Homicides in Chicago this year are down 21 percent compared to last year - at 305 compared to 389, according to the Chicago Police Department.
(Writing by Noreen O'Donnell, Editing by Alex Dobuzinskis and Sandra Maler)