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NEW YORK (CBSMiami/AP) — Police are trying to find out what prompted people to report hearing gunshots at Kennedy Airport on Sunday night – triggering evacuations and panic among travelers.

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Investigators determined there were no guns or ammunition involved, but videos and photos showed people cowering behind chairs and running across a road to escape the evacuated terminals.

One video showed startled travelers scrambling for cover as a team of police officers swept through the terminal, weapons drawn, shouting for people to get down on the ground.

Police evacuated Terminal 8 as a precaution around 9:30 p.m. Sunday after receiving a 911 call reporting the sound of a gunshot near the departures area.

The initial report that resulted in the “robust response” was “not a hoax,” said airport police spokesman Joe Pentangelo, but rather appeared to be “an initial reaction to people running.”

It’s not clear what had prompted the people to run.

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Port Authority police called in officers from the New York Police Department to assist with the investigation.

A short time later, police closed Terminal 1 after receiving reports of a gunshot there. A highway approaching the airport also was shut down.

Demetrius Pipkin told WPIX-TV he was in Terminal 1 waiting for his Norwegian Airlines flight when passengers were “told to get on the floor and take cover behind any and everything we could find.”

Pipkin described the terminal as a “madhouse” with panicky passengers eventually bolting for the nearest exists.

According to the flight tracking company, FlightAware, all inbound flights were held at their origin at until 11:30 p.m. “due to security.”

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