Police were investigating what caused people to report hearing gunshots at Kennedy Airport on Sunday night, triggering a series of evacuations and some panic among travelers spooked by the heavy police response.

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.

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.”

(AP)