There was total chaos at New York's John F. Kennedy International Airport on Sunday night as reports of an active shooter spread through social media and on the ground.

Hours later, it became apparent that it was a false alarm. But by this stage, terminals had been closed down, people had been evacuated and hysteria had overtaken the airport. The heavy-handed police presence seen in video footage terrified passengers inside the terminals.

Now, it appears the incident may have been sparked by people simply celebrating Usain Bolt's win in the 100-meter spring at the Rio Olympics. According to NBC, authorities believe cheering, clapping and banging from Olympic viewers may have been mistaken for gunfire.

A law enforcement official told NBC the whole debacle began when a woman disembarking from a plane said she had heard gunshots. This report correlated with a report from two other officials, according to the network. It is unclear how the incident escalated so rapidly.

#NOW: Unconfirmed reports of shots fired @ JFK Terminal 8. #SOD #ESU & @PAPD #ESU on the scene. Situation unfolding pic.twitter.com/VcYMmMbfPj

— NYPD Special Ops (@NYPDSpecialops) August 15, 2016

UPDATE: @PAPD & #NYPD #ESU are clearing Terminal 1 & 8 (Departures). There is nobody shot. It appears that no shots have been fired.

— NYPD Special Ops (@NYPDSpecialops) August 15, 2016

After the alarm was raised, Terminal 8 and Terminal 1 were evacuated immediately. No further information was provided, except a voice over a loud speaker telling passengers to leave their bags behind and exit the terminal.

In a video from the scene, heavily armed police can be seen rampaging through the airport terminal screaming "everybody get down on the ground." People can be seen running for shelter, while the Instagram user who shared the video said people were praying and crying.

Frightening when everyone around you is praying and crying. #jfk 💔

A video posted by D A N Y E L L E S A D A (@danyellesada) on Aug 14, 2016 at 8:47pm PDT

Another person at the airport, Ryan Craver, Periscoped the incident. Passengers can be seen evacuating JFK with their hands in the air.

LIVE on #Periscope: Evacuating #jfkairport https://t.co/2zB89zFuV8

— Ryan M Craver (@ryanmcraver) August 15, 2016

A ground stop was enforced by the Federal Aviation Authority for "security" reasons, it confirmed to Mashable. Just after midnight, the NYPD and Port Authority gave the all clear, saying all terminals had been searched and there was no evidence of a shooter. The Port Authority has been contacted for comment.

Statement regarding situation at John F. Kennedy International Airport. #JFK #PAPD @PANYNJ @NY_NJairports pic.twitter.com/eOBR0UnzVY

— Port Authority NY&NJ (@PANYNJ) August 15, 2016

JFK UPDATE: All terminals searched & cleared. Negative results. All affected terminals will resume operations shortly. No shots were fired.

— NYPD Special Ops (@NYPDSpecialops) August 15, 2016