Three people were killed and five others injured Sunday night in a mass shooting at El Camaron Gigante Mariscos & Steakhouse, a restaurant located just outside Phoenix, according to Glendale police. Authorities believe multiple shooters were involved, but no suspects have been arrested.

The incident occurred around 7:45 p.m. local time during what appeared to be a crowded event at the restaurant. "It was very chaotic," said Officer Moroni Mendez, spokesperson for the Glendale Police Department. "We've got multiple calls of a shooting that happened at an establishment."

Upon arrival, police found what they described as an "enormous scene" with victims wounded by either gunfire or shrapnel. "Three people died from their injuries and five other people were injured," Mendez said during a briefing. "Obviously there was a lot of people here... Anyone who has information, please come forward."

Authorities confirmed that several individuals have been detained for questioning, though none have been taken into custody. Mendez said no suspects have been taken into custody, adding that investigators are still trying to determine what led to the violence. No police or security officers discharged their weapons, and officials said there is currently no ongoing threat to the public.

"We want to make sure we do a complete and thorough investigation and do right by the victims," Mendez said. "Whether they know each other, whether they're related, whether they're allies or opponents - we don't know yet, and that's what we're trying to solve and figure out."

Lupe Rodriguez, a bystander who escaped the scene unharmed, described the horror to KPHO-TV. "There was a man on the ground and it didn't look like he made it," he said. "His father was yelling out his name. It was pretty bad."

Police have not released the identities of the victims. Mendez stated that officers expect to remain on site into the morning hours as they gather evidence and interview witnesses.

The shooting marks one of 97 mass shootings so far in the United States this year, according to data from the Gun Violence Archive, which defines mass shootings as incidents in which four or more people are shot or killed, excluding the shooter.