OKLAHOMA CITY – At least 23 people were injured after gunfire erupted Sunday night at a lake party near Oklahoma City, authorities said.

The shooting happened around 9 p.m. at a campground near Arcadia Lake, about 13 miles north of Oklahoma City, Edmond police spokesperson Emily Ward said.

Edmond police said the party had been promoted on multiple social media platforms and drew a large crowd of young adults from across the metro area. Police said it was not a permitted or reserved gathering.

Victims suffered injuries “ranging in severity, including gunshot wounds,” police said Monday. Integris Health said 13 people were hospitalized after the shooting.

By Monday afternoon, six of those hospitalized had been released, the health system said. Seven remained hospitalized, ranging in age from 16 to 30. Three were in critical condition and four were in serious condition.

“This is obviously a very terrifying situation,” Ward told reporters at the scene. “We are working extremely hard to find these suspects and help these victims.”

Authorities believe two men wearing ski masks opened fire, CNN affiliate KOKH reported. Edmond police declined to release suspect details Monday, citing the active investigation.

No suspects were in custody, but police said they do not believe there is an ongoing threat to the public.

The Oklahoma shooting came during a weekend that also saw shootings at youth or young adult gatherings in Indianapolis and Texas. In Indianapolis, a post-prom party shooting left one woman dead and at least two others wounded, WTHR reported. In Amarillo, two teenagers were killed and at least 10 others were injured at a party involving juveniles and young adults, police said.