Thirteen people were arrested when Suffolk County police broke up what they called an "unauthorized fight club event" in Shirley yesterday evening.

Officers said they responded to the Brookhaven Aquatic Center parking lot around 6 p.m. for reports of gunshots. At the scene, police said they found a large fight between several people who were at the fight club.

Investigators said a boy, 17, and a man, 19, were injured when one of the people there discharged a blank-firing gun during the scuffle. The two victims were taken to a hospital and treated for injuries not considered life-threatening.

"Scary to know that a gunshot went off, and thank God my kid wasn't there," Mastic Beach resident Mandee Pecoraro said.

Mastic Beach resident Devine Brown, 25, faces the most serious charges, including assault, menacing, prohibitive use of a weapon and unlawful assembly. He is scheduled to be arraigned at First District Court in Central Islip today.

The other 12 arrested were charged with unlawful assembly and issued field or desk appearance tickets:

Brookhaven residents said this is the latest incident that has marked a drop in the local quality of life.

"Definitely, it has diminished," Mastic Beach resident James Metz said.

Brookhaven Town Supervisor Dan Panico said information about the "fight club" was spread through social media. He called for stricter laws that punish people who make money off content that leads to crime.

"An example needs to be set because the good people of Mastic, Shirley, Mastic Beach and elsewhere have had it with all this stupidity," he said.

Panico said the town will share all video from the Aquatic Center with Suffolk County police to help with the ongoing investigation.

Suffolk County police detectives are asking anyone with information on the incident to contact the 7th Squad at 631-852-8752.