At least 12 people were hospitalized after gunfire broke out during a party at a campground in Oklahoma on Sunday night, local officials said.

The shooting at Arcadia Lake in Edmond happened just after 9 p.m., the Edmond Police Department said on X. The extent of the injuries and their exact nature were not immediately clear.

"Edmond Police, along with Oklahoma City Police and the Oklahoma Highway Patrol, responded to the scene and located numerous victims. Emergency personnel transported 10 victims to various metro-area hospitals," police said.

No one was in custody as of early Monday, and it was unclear what preceded the gunfire.

As of early Monday, nine shooting victims were being treated at the Integris Health Baptist Medical Center in Oklahoma City while three were being treated at victims at Integris Health Edmond Hospital, a spokesperson for the hospitals told NBC News.

"These are all victims of the shooting in Edmond this evening. No other patients that Integris is aware of at their hospitals involved in the shooting," the spokesperson said.

The campground is about 20 miles north of Oklahoma City.

The lake, popular for watersports, was created in 1987 in a joint operation between the City of Edmond and the U.S. Army Corps of Engineers.