-Hours later in Oslo, drones appeared over the Akershus fortress, prompting arrests of two foreign nationals with Singapore passports; Oslo Airport later reopened. Poland warned it may shoot down threats, while NATO unveiled “Eastern Sentinel” to bolster the alliance’s eastern airspace deterrence. Drones Keep Flying All over NATO AirspaceUnidentified drones were detected Sept. 22 flying over Denmark and Norway. Copenhagen Airport spokesperson Lise Agerli Kjurstein confirmed that the airspace was closed around 8:30 p.m. because of the sighting. According to Estonian Foreign Minister Margus Tsahkna, the NATO member-nation is initiating consultations under Article 4 of NATO.