Air traffic above the southern Dutch city of Eindhoven has been suspended after unidentified drones were spotted near the airport.
Drones were first observed late on Friday over the nearby Volkel air force base. Weapons were deployed to try to shoot them down but the devices got away.
Following more drone sightings near the main airport on Saturday, the airspace in the area was closed to both civilian and military flights. Dutch Defence Minister Ruben Brekelmans said “counter-drone assets” were ready to intervene.
It is the latest in a series of such incidents at military installations and airfields in northern Europe in recent months. Russia has denied accusations it was involved in them.
As well as being used by the Royal Netherlands Air Force, Volkel Air Base hosts a US Air Force squadron as part of Nato.
Officials said that for security reasons they would provide no details about how the drones were first spotted on Friday or what action was taken to try to bring them down.
Drones have been sighted at other Dutch air bases in the past few weeks, as well as facilities in neighbouring Belgium, Denmark and Germany.
A lack of evidence pointing to their origins has plagued investigations into the incidents since they began in September, as in many cases the drones depart after a while.
Some European officials have attributed the sightings to “hybrid warfare” on the part of Russia, as the nations that have been targeted are all allied to Ukraine.
But the Kremlin has denied it has anything to do with past incursions.
Defence ministers from 10 EU countries have agreed to create a “drone wall” in response to the sightings, while some individual nations have sought to secure anti-drone defence measures.