An accidental hijack warning set off from the cockpit of a plane triggered a big security operation at Amsterdam's Schiphol Airport on Wednesday night, a Spanish airline and Dutch military police said. Air Europa said in a tweet that the scare that sent emergency services rushing to the airport was a false alarm.

The warning that triggers hijack protocols at airports "was activated, by mistake", on a plane that was bound for Madrid, the carrier tweeted. It did not say who activated the warning or how.

"Nothing has happened, all passengers are safe and sound waiting to fly soon. We deeply apologize," the airline said.

The Dutch military police service earlier said it was responding to a suspicious situation at the airport on the outskirts of Amsterdam. Dutch media reported that heavily armed arrest teams and other emergency service forces were deployed to the airport.

The military police said in a tweet that it followed all protocols following the alarm and would now investigate how the report of a hijack or hostage situation came from the plane's cockpit.

"The situation is now safe," airport spokesman Dennis Muller told The Associated Press. "All flights can now depart."

The local mayor responsible for the Schiphol region, Marianne Schuurmans, said it took two hours to give the all-clear signal.

"Further investigation by the military police must determine exactly what happened," Schuurmans said.