Photo: Deadly shooting at the 4th of July parade in suburban Chicago

At least six people were killed and 24 were injured in shooting at the Fourth of July parade in Highland Park, a suburb of Chicago.and cops are looking for a shooter who likely fired at the festivities from a rooftop, police said Monday.

Highland Park Police Commander Chris O’Neill, who commanded the incident at the scene, urged people to take cover at the scene while authorities search for the shooter.

“This morning at 10:14 a.m., our community was terrorized by an act of violence that shook us to the core,” Mayor Nancy Rothering said at a press conference. “Our hearts go out to the families of the victims at this devastating time. On a day when we come together to celebrate community and freedom, we instead mourn the tragic loss of life and fight the horror that has befallen us.”

Hundreds of parade participants, some of whom were visibly bloody, fled the parade route after gunshots rang out, leaving their belongings.

By noon, signs of a joyous event, suddenly turned into horror, filled both sides of Central Street, where the shooting had taken place. Dozens of prams, some with American flags, abandoned children’s bikes, and a helmet covered in a Cinderella image were thrown in the haste. Blankets, sun loungers, coffee and water bottles were knocked over as people ran.

Police and cars fill the street.

Police search downtown Highland Park, Illinois after the shooting.

(Tyler Paciak LaRiviere/Chicago Sun-Times via AP)

A man stands on the sidewalk next to a pool of blood.

Blood puddles on the ground in Port Clinton Square in Highland Park.

(Lynn Sweet/Chicago Sun-Times via AP)

Police search a downtown street near a row of overturned camping chairs.

Police search the Highland Park area in the city center looking for the perpetrator.

(Tyler Paciak LaRiviere/Chicago Sun-Times via AP)

A police officer raises a yellow warning tape to let a police car through.

Rescuers are on the scene on Monday.

(Jim Wondruska/Getty Images)

Chairs and empty carriages line the parade route.

Items left behind by parade participants who fled the route when the shooting started.

(Tyler Paciak LaRiviere/Chicago Sun-Times via AP)

Several people stand on the sidewalk among a pile of empty chairs, strollers and scooters.

People check their belongings left on the parade route after the shooting.

(Nam Yu Ha/Associated Press)