Washington DC - A 15-year-old was killed and three other people were injured after shots were fired at the Moechella Music Festival in the heart of Washington DC on Juneteenth, according to the DC Metro Police.

An officer was among those injured and is currently hospitalized in stable condition.

"We can confirm that one of our members working in the area of 14th and U St NW has been shot," the union for the District of Columbia's Metropolitan Police Department tweeted. "The member has been transported to the hospital and is in stable condition."

A fight had previously broken out and law enforcement were in the process of breaking up Moechella, a street festival mixing go-go music with the fight against gentrification now on its third edition, but considered an "unpermitted" event.

People then reportedly began running when the gunshots rang out. Videos were posted on Twitter showing attendees fleeing.

Washington DC Metro Police Chief Robert Contee said multiple firearms were recovered at the scene.

Both the cops and DC Mayor Muriel Bowser zeroed in on the organizers for holding the festival without a permit. "We have a child who was killed today at an event that did not have any proper planning," Bowser said. "We need some accountability here."

Some Twitter users who said they were on the scene claimed the police presence at the event was noticeably heavy throughout the night and noted that previous editions had passed without incident.