It was the mayor's first spoken statement since 13 people were shot in the Cornell Square Park near 51st and Wood.
"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. That's what gun violence does," said Mayor Emanuel.
Relatives of Deonta Howard, the 3-year-old boy wounded in the shooting, were present for the mayor's remarks.
" These rude, disrespectful, inconsiderate people that just go around shooting up parks, people's homes, cars, not knowing kids in there. It's crazy, it's got to stop," said Semehca Nunn, victim's grandmother.
Superintendent Garry McCarthy appeared alone at a late-morning news conference on Friday, revealing he'd been in constant telephone contact with Emanuel.
"I have an obligation to keep him posted on what's going on. He wants an arrest," McCarthy said.
"You say you got all these cops on the street... where are they?" said Mitchell Gary.
Like the mayor, Gary also wants answers. His brother and nephew were among the victims. He called Emanuel's public safety efforts a failure.
"I give him an F on his report card because he's not standing up and doing what he's supposed to be doing, OK?" Gary said.
At the crime scene, satellite trucks beamed reports internationally, some calling Chicago the most violent big city in the country.
"Chicago is actually in the middle of the pack in big-city America for gun violence," said Prof. Harold Pollack, University of Chicago.
Other state and local politicians added their outrage.
"It's heartbreaking to think that 11 or 12 innocent people would be shot, seriously injured," said US Sen. Dick Durbin, (D), Illinois.
"We have to make sure that all of us of good faith come together to take on this violence that's afflicting our society," said Gov. Pat Quinn.