Twenty people, including a teenager, were injured early Sunday in a shooting at a 24-hour art festival in Trenton, New Jersey, the Mercer County Prosecutor's Office said.
One suspect was killed, and another one was taken into custody, officials said.
"Multiple weapons have been recovered," prosecutor Angelo Onofri said. "Twenty individuals were treated for a variety of gunshot wounds as well as other injuries."
Among the injured is a 13-year-old, who is in extremely critical condition, the prosecutor said.
Witnesses told CNN affiliate WPVI the shooting happened around 2:45 a.m. at the Art All Night-Trenton festival at the Roebling Wire Works Building on the south side of the city.
"All of a sudden, my brother goes to me, 'You hear that gunfire?' I go, 'It sounds like fireworks.' He said, 'No, that's gunfire.' Next thing you know, we turn around and everybody's running down the street. All hell broke loose," Angelo Nicolo of Trenton told the station.
Nicolo saw one person with a gunshot wound, he said.
"I saw two police officers escort a guy that got shot in the leg. They bandaged him up and whisked him away before the ambulance came here. It was pretty gnarly," Nicolo said.
Police are questioning witnesses to determine if more suspects could be at large, WPVI reported. The dead suspect was a 33-year-old man, police told the station.
Before it was canceled, the festival had been scheduled to run from 3 p.m. Saturday to 3 p.m. Sunday. It featured more than 1,500 works of art, live murals and graffiti, dozens of musical performances and a film festival. The event is in its 12th year, its website says.
"We're still processing much of this and we don't have many answers at this time, but please know that our staff, our volunteers, our artists and musicians all seem to be healthy and accounted for. Our sincere, heartfelt sympathies are with those who were injured," festival organizers said on Facebook.
The Mercer County's Prosecutors Office Homicide Task Force will lead the investigation as there was an officer-involved shooting.