What was supposed to be a carefree day at the beach turned chaotic Thursday evening, as police were forced to break up a crowd of approximately 500 teenagers who had gathered at Jones Beach for an unofficial “Senior Cut Day.”

According to state park officials, the teens were from high schools in Queens and Nassau County. They were drawn to the beach by a flyer that had circulated on social media.

Witnesses described a scene that quickly spiraled out of control.

Authorities reported several physical altercations throughout the evening.

As the situation escalated, police moved in to restrict access to parts of the beach in an effort to prevent further violence. There were no reports of serious injuries.

The incident comes less than a one week after officials in nearby Long Beach closed their beaches preemptively to prevent a similar gathering. Last June, a teenager was shot in Long Beach when a crowd of roughly 2,000 teens gathered and police attempted to intervene.

Longtime beachgoers say the recent trend is a stark contrast to the peaceful summers of the past.

“The beach was never like this,” said one local. “We came here as kids—it was so calm. But now it’s just crazy.”

Despite the disruption, state parks officials say Jones Beach is expected to open as scheduled on Friday.

Nassau County police say one person was arrested for menacing and disorderly conduct.