The Dutch Royal Military Police are responding to a "suspicious incident" on a plane at Amsterdam's Schiphol airport on Wednesday.
The airport said on Twitter that the Royal Netherlands Marechaussee, a branch of the Dutch military, was "investigating a situation on board" the plane at the airport and several gates at the airport was under lockdown. The federal police declined to provide any details about the nature of the incident.
"The only thing I can tell you is that the military police is investigating a suspicious situation," Hans Van Kastel, an airport spokesman, said in an interview. Mr. Van Kastel said the situation began about 7 p.m. local time at the airport, which is Europe's third busiest, after London's Heathrow and Paris Charles de Gaulle Airport.
The airport wrote on Twitter that passengers and crew were safely off board the plane as investigation continues.
While authorities have not confirmed the details of the plane, some reports on Twitter said the incident took place on board an Air Europe plane to Madrid with at least 27 people thought to be on the flight. Meanwhile, U.K.'s the Sun claimed, citing Twitter posts, that three men armed with knives were trying to hijack a plane.
However, these reports surfacing on Twitter cannot be confirmed.
This is a developing story.