A mass shooting at a crowded bar on an idyllic South Carolina island left at least 4 people dead and another 20 injured, officials said.

The shooting happened early Sunday at Willie’s Bar and Grill on St. Helena Island. A large crowd was at the scene when sheriff’s deputies arrived and found several people suffering from gunshot wounds.

“It was learned that hundreds of people were at the location when the shooting occurred,” the Beaufort County Sheriff’s Office said in a statement. “Multiple victims and witnesses ran to the nearby businesses and properties seeking shelter from the gunshots.

Four people were found dead at the scene, and at least 20 people were injured. Among the injured, four were in critical condition and taken to area hospitals for treatment. There was a party for alumni of Battery Creek High School at the bar, CBS affiliate WTOC-TV reported.

The victims’ identities were not released.

Bar owner Willie Turral told WTOC-TV that he was “still processing everything” that happened.

“You know that things like this could happen, of course, you try to take the best efforts that you can to deter any situation like this from occurring,” Turral said. “But when something like this happens, I mean in your heart of hearts, at least in mind, you know, I never really expected to ever see anything like this.”

The sheriff’s office said it is investigating “persons of interest,” but no arrests have been made.

“This is a tragic and difficult incident for everyone. We ask for your patience as we continue to investigate this incident. Our thoughts are with all of the victims and their loved ones,” the sheriff’s office said.

“COMPLETELY HEARTBROKEN to learn about the devastating shooting in Beaufort County,” U.S. Rep. Nancy Mace posted on X. “Our prayers are with the victims, their families, and everyone impacted by this horrific act of violence.”