Six persons were killed and over 36 injured after a gunman opened fire on an Independence Day parade in a suburban area of United States’ Chicago on Monday, reported Reuters. The police said they have arrested a suspect identified as 22-year-old Robert E Crimo III.

The shooting took place at 3 pm GMT (or 8.30 pm local time) in Chicago’s suburb of Highland Park. A video on Twitter showed the participants of the July 4 parade running away in terror as shots were fired.

Five adults died on the spot and another person succumbed to his injuries at a hospital. One of those who died is a Mexican citizen, a senior official said. He added that two of those wounded were also Mexican citizens.

Most of those hurt had gunshot wounds, said Jim Anthony, a spokesman for the NorthShore University HealthSystem. Twenty-six of them were taken to the Highland Park hospital and they were aged between 8 and 85, said a doctor at the medical facility.

“It is devastating that a celebration of America was ripped apart by our uniquely American plague,” Illinois Governor JB Pritzker said at a news conference, The Associated Press reported. “I’m furious because it does not have to be this way... while we celebrate the Fourth of July just once a year, mass shootings have become a weekly – yes, weekly – American tradition.”

The police said that the shooter fired at the crowd from the rooftop of a building. His motive, however, is not clear. Charges will be filed, the Highland Park Police said.

A participant identified as Sara told Reuters that she had attended the annual parade for most years since her childhood.

“Not even five minutes after, very shortly after, the police and firetrucks part of the parade had gone by I heard ‘pop, pop, pop, pop, pop,’” she said, explaining that she first thought the sounds were of muskets sometimes used in parades.

“I looked and there were no muskets,” she added. “The popping didn’t stop... again it went ‘pop, pop, pop, pop, pop’ and I turned and I said ‘those are gun shots, run!’”

In a statement, US President Joe Biden said he and his wife were “shocked by the senseless gun violence that has yet again brought grief to an American community on this Independence Day”.

Biden referred to the bipartisan gun-reform legislation he signed last month but said that there is much more work to do.

“I’m not going to give up fighting the epidemic of gun violence,” he added.

At the time Biden had signed the Bipartisan Safer Communities Act, the US had recorded at least 254 mass shootings this year, according to CNN.

The law puts in place tougher background checks for buyers younger than 21 years and expands restrictions on domestic violence offenders on owning firearms. The Act also provides incentives to those states that would pass laws that allow guns to be temporarily confiscated from people deemed to be too dangerous to possess them by a judge.

Efforts to introduce gun control laws had gained momentum after an attack at the Robb Elementary School in Texas’ Uvalde city. The attack was carried out by 18-year-old Salvador Ramos, who was eventually killed by responding officers. Ramos had shot his grandmother before attacking the school.