An apparent false alarm prompted a major security alert at Amsterdam's main airport late Wednesday, drawing a major emergency response involving Dutch military police and the evacuation of passengers.

Air Europa, whose pilot entered a code that indicated a hijacking, confirmed the incident was a false alarm.

"False Alarm. In the flight Amsterdam - Madrid, this afternoon was activated, by mistake, a warning that triggers protocols on hijackers at the airport," the airline tweeted. "Nothing has happened, all passengers are safe and sound waiting to fly soon."

The Dutch Royal Military Police tweeted earlier they were investigating a "suspicious situation" at Amsterdam Airport Schiphol, which is a major European hub on the outskirts of the city.

"The Royal Netherlands Marechaussee is currently investigating a situation on board of a plane at Amsterdam Airport Schiphol," the airport said. "We keep you posted."

Royal Military Police later tweeted the passengers and crew were "safely" off the plane and that the investigation continued, without releasing additional details.

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Dutch news outlet NU.nl reported there was a GRIP-3 situation underway, which means "Threat to the well-being of (large groups of) the population within one municipality."

Photos posted to social media from people at the airport showed areas cordoned off with police tape, as officers appeared to be putting parts of the airport under lockdown.

Two trauma helicopters also responded to the airport, NU.nl reported.

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Flight-tracking website Flightradar24 said the situation was affecting flights at the airport's Piers D and E, even-numbered gates. Arriving flights to the D and E even gates were being held away from the terminal area, according to FlightRadar24.

Additional details were not immediately available.

Fox News' Bradford Betz contributed to this report.