WASHINGTON -- Two gunmen opened fired at an arts and music festival in Trenton, state of New Jersey, early Sunday, during which a suspect was killed and at least 22 people were injured, authorities said.

Of 17 people treated for gunshot wounds, four people, including a 13-year-old boy, remain in critical condition late Sunday morning, Mercer County Prosecutor Angelo Onofri told reporters.

The rest suffered other injuries during the shooting.

Onofri said one suspect is believed to have been shot and killed by a police officer, while the other has been arrested.

Local reports say the two suspects opened fire around 2:45 am Sunday during the Art All Night, a 24-hour event that draws thousands of people.

Witnesses reported people panicking and running, causing a stampede after the gunfire.

Onofri said the shooting appears to be related to a dispute among people at the event.

The remainder of the two-day festival has been canceled, according to reports.