One person was killed and at least 12 others were injured in a shooting at a party in Oklahoma City early Saturday, police said.

Two groups got into a “verbal altercation” inside an event center about 12:30 a.m. local time and the fight spilled into a parking lot, where shots were fired, Sgt. Jon Skuta with the Oklahoma City Police Department told CNN.

“Those people then went back into the event center where the shooting continued,” Skuta said, adding that investigators believe this was an isolated incident.

One person was pronounced dead at the scene and at least 12 others showed up at hospitals with gunshot wounds, Skuta said. No information was available on their conditions or ages.

Skuta said no arrests had been made as of early Saturday, but people have been detained.

It’s unclear what led to the fight or how many people fired.