A Juneteenth weekend gathering in a Willowbrook strip mall parking lot was becoming a yearly tradition among residents of the Hinsdale Lake Terrace apartments.

Barbecue chicken, a card table, plastic cups for drinking. Even DuPage County sheriff’s deputies stopped by the festivities as the party moved into the early hours of Sunday morning.

But the gathering turned violent as gunfire broke out in the crowd of several hundred people, killing one person and wounding 22 others, according to the sheriff’s office.

In a matter of seconds, shots flew across the parking lot near Route 83 and Honeysuckle Rose Lane.

“It was chaotic. Chaos, pure chaos,” said Nayetta Reed, 43, who was in the crowd but was unhurt.

Sheriff’s deputies in the area heard the gunfire just before 12:30 a.m. and responded, the sheriff’s office said.

The wounds ranged from grazes to serious injuries, Joe Ostrander, battalion chief of the Tri-State Fire Protection District, told reporters earlier in the day. He said two people were in critical condition.

Some of the victims were taken to hospitals in DuPage, Will and Cook counties, authorities said. Several got to hospitals on their own.

It was unclear what prompted the shooting or how many people were being sought. No one was in custody. Authorities did not disclose the age or conditions of the victims.

Before the shooting, there were two separate fights between teenage girls, Reed said. Sheriff’s deputies had intervened as well, witnesses told the Sun-Times. But Reed and other witnesses believed the shooting was unrelated to the previous fights.

Several witnesses told the Sun-Times the gunfire came from the far south side of the lot, away from where people were gathering in front of BCD Liquors and Five Star Pantry.

Reed said she heard at least 100 shots in 10 or 15 seconds.

Residents of the nearby apartment complex had held similar Juneteenth parties in the same lot over the last two years, Reed said. It had always been peaceful, she said.

This year, though, the crowd size had become “excessive,” Reed said, estimating that there were between 200 and 300 people.

“Since Juneteenth has come about, we’ve been celebrating. And usually the sheriffs are out here with us. It’s very controlled, it’s peaceful,” Reed said. “I don’t know what happened. I really don’t know what happened last night. It just went left.

“We’ll probably never do another one,” she said.

Later Sunday morning, residents of the apartments looked over police tape as investigators placed dozens of evidence markers throughout the parking lot strewn with cups, shoes and a turned-over trash can.

Witnesses said they think the number of people shot is higher than officially reported. Some people with minor wounds have avoided going to the hospital, Reed said.

One man Sunday said he was shot in his lower leg and had gone to a hospital but left after waiting several hours to be seen by a doctor. He asked not to be named.

David Barnes, 25, said he ran from the crowd when the shooting started. The lot was filled with parked cars.

He said he noticed a lot of new people in the celebration, which had typically been attended by longtime residents of the nearby apartments.

“That’s how it had been. Everybody knew each other. That’s how it should’ve been,” he said. The party had started around 4 p.m., with grilling, Barnes said.

Gov. J.B. Pritzker said he was closely monitoring the investigation into the shooting.

“Gathering for a holiday celebration should be a joyful occasion, not a time where gunfire erupts and families are forced to run for safety,” Pritzker said in a statement. He said gun violence is a public health emergency and that he remained committed to banning “dangerous weapons.”

U.S. Rep. Sean Casten said he was heartbroken by the shooting.

“We live in a tragic reality where you cannot go to school, go to the grocery store, go to your place of worship, or celebrate holidays like the Fourth of July or Juneteenth without fear of being shot,” Casten said in a statement.

Sunday’s shooting is among at least 310 mass shootings in the U.S. this year, according to the Gun Violence Archive.

Almost a year ago, a mass shooting in north suburban Highland Park killed seven people and wounded nearly 50 others.

Police asked anyone with information about what happened to call (630) 407-2400.

Contributing: AP