Initial reports: Alarm sounds

The news spread like wildfire: A police operation led to the immediate evacuation of the secure area. Passengers were hastily escorted from the sensitive area as firefighters and emergency personnel arrived. Airport operators reported disruptions to departures ; arrivals remained unaffected for the time being.
The cause remains unclear – rumors of a fire alarm or technical malfunctions are circulating. Authorities are remaining tight-lipped, and travelers are wandering aimlessly through the terminals. Long lines and delays are the norm, while air traffic is at a standstill.
Let’s dig deeper: Which forces are involved?