Witnesses have spoken of their horror at seeing children 'shot in the head' during the 4th of July parade massacre shooting - with the gunman still at large.
As families and children sat waiting for the annual procession in Highland Park, Illinois, US, at 10am local time, hundreds of families were forced to flee for their safety after a gunman opened fire from a roof.
Witnesses have recalled the moment a shooter opened fire from the roof of an outdoor fitting store - and shot people in the crowd including children.
Parade gatherers initially believed the gun shots were Independence Day fireworks.
The FBI has launched a manhunt for the shooter, with the suspect named as Robert "Bobby" E. Crimo III.
He is driving a silver Honda and is considered armed and dangerous.
Witness Larry Bloom told NBC Chicago at first people thought the popping sound was part of the parade.
"You heard like a 'pop, pop, pop,' and I think everybody kinda thought maybe it was a display on one of the floats and then it just opened up," he said.
"I was screaming and people were screaming. They were panicking and and they were just scattering and I, you know, we didn't know. You know, it was right on top of us."
Police confirmed the gun shots began less than 15 minutes after the start of the parade as he launched the attack from a roof and aimed his rifle towards children.
Parade-goers left behind chairs, prams, bicycles and blankets as they fled the event route on Central Street in the city's downtown area.
It is understood at least 24 people were rushed to hospital as the FBI has launched a manhunt for the shooter who remains active
An eyewitness named Zoe told CNN : "'All of a sudden everyone behind us started running. I looked back, probably 20 feet away from me, I saw a girl shot and killed. I saw her die. I’ve never seen anything like this."
She added: 'One man had been shot in the head, his ear, he was bleeding all over, and he was, like, I’m just happy that’s all happened.
"There was another girl that got escorted out that was shot in the leg. We were hiding in the basement for quite a while.
"I mean, someone, 20 feet away, you know, someone — and then we went back to get our cars and we saw the streets were quite littered. It looked like a battle zone and it’s disgusting.
"It was — you know, everyone obviously remembers the Boston marathon massacre, like a happy marathon, and it’s just a happy day. It’s the Fourth of July.
"It was the kid’s parade and dog parade. Little kids on bicycles and pets. That’s who had just walked by."
Cops later recovered a 'rifle at the scene but witnesses described it as more of a semi-automatic weapon as the shots fired off in quick succession.
Zoe said: "A rifle? No, no. It was an automatic weapon. It was pop, pop, pop, rifles don’t do that."
The devastating massacre has promoted politicians including the Governor of Illinois to call for gun control and to demand gun reform since the Uvalde school shooting on May 24.
Katherine Clark, Assistant Speaker of the U.S. House, tweeted: "The fact that no place in the USA is safe from gun terror means no place is truly free. Heartbroken for Highland Park."
