22-year-old gunman, who opened fire on an Independence Day parade in Highland Park city, killing at least six people and wounding 30 others, is now under arrest, US police say.

Approximately 40,000 deaths a year are caused by firearms in the US, according to the Gun Violence Archive website.
Approximately 40,000 deaths a year are caused by firearms in the US, according to the Gun Violence Archive website. (AFP)

Police have arrested a suspect after a mass shooting left six dead at a US Independence Day parade in a wealthy Chicago suburb, casting a dark shadow over the country's most patriotic holiday.

Robert Crimo, 22, was identified as a "person of interest" and became the target of a massive manhunt across the town of Highland Park in Illinois, where a rooftop gunman with a high-powered rifle turned a family-focused July 4 parade celebration into a scene of death and trauma.

Firing into the holiday crowd, the shooter triggered scenes of total chaos as panicked onlookers ran for their lives, leaving behind a parade route strewn with chairs, abandoned balloons and personal belongings.

Emergency officials said around two dozen people, including children, were treated for gunshot injuries, with some in critical condition.

Another official Jennifer Banek said the five people killed at the parade were adults and she doesn't have information on the sixth victim who was taken to a hospital and died there.

After a brief car chase, Crimo was taken into custody "without incident," Highland Park police chief Lou Jogmen told reporters.

Earlier, police had warned that he was armed and "very dangerous."

READ MORE: US accounted for 73 percent of global mass shootings

'Epidemic' of gun violence

In another July 4 shooting, two police officers were wounded when they came under fire during a fireworks display in Philadelphia, major US news outlets reported.

CBS News aired video taken from a high-rise building showing crowds fleeing in panic as fireworks burst in the sky. The circumstances of that shooting were not immediately known.

The shootings are part of a wave of gun violence plaguing the United States, where approximately 40,000 deaths a year are caused by firearms, according to the Gun Violence Archive website.

The latest shooting cast a dark cloud over America's Independence Day, in which towns and cities across the country hold similar parades and people, many dressed in variations on the US flag, hold barbecues, attend sports events and gather for firework displays.

"This is the day that we celebrate our country. This is also a day that our freedom got stolen from us -- because many of us residents here, in this building even, we're all locked down," Emily Prazak, who marched in the parade, said.

US President Joe Biden pledged to keep fighting to end the "epidemic" of gun violence in America after the deadly mass shooting.

"I'm not going to give up fighting the epidemic of gun violence," he said, noting he had signed the first significant gun control measures in decades into law in late June, but that "much more work" remains.

The legislation expands criminal background checks for some gun buyers, bars a larger group of domestic-violence offenders from purchasing firearms and funds programs that would allow authorities to seize guns from troubled individuals.

Critics say the new measures do not go far enough.

READ MORE: NRA to stage big gun show in Texas as US mourns massacre victims

Source: TRTWorld and agencies