Belgium halted air traffic at Brussels Airport on Nov. 4 following reports of a drone sighting, according to the Belga News Agency.
The shutdown came just one day after the Belgian military was instructed to shoot down any unidentified drones breaching sovereign airspace, following three consecutive nights of suspicious airspace violations.
Officials said that large, high-altitude drones repeatedly entered restricted airspace from the end of October through to the start of November over the the Kleine Brogel airbase, one of Europe’s most sensitive military sites that hosts US-made nuclear-capable F-16s.
On Nov. 4, the violations appeared to escalate as a drone was seen around Brussels Airport shortly after sightings of six drones over Kleine Brogel, the Belga News Agency reported.
Local police were dispatched to the airbase after residents sounded the alarm and spotted two of the drones.
At the airport, Kurt Verwilligen, a spokesperson for Belgium’s air traffic control agency Skeyes, said: “For safety reasons, all air traffic has been halted for the time being.”
The smaller Liege Airport also said it was closed after drones had been spotted in the area.
It is not yet clear when flights will resume.
This marks the first occasion on which Brussels Airport has been closed due to drone activity, though similar incidents took place repeatedly across Europe in September and October, including in Copenhagen, Oslo, Aalborg and Munich.
On Friday, Berlin-Brandenburg Airport also diverted flights following a drone alert.
In response to the incursions over Kleine Brogel, Belgian Defense Minister Theo Francken told Belgian outlet RTBF that the drones “come to spy, to see where the F-16s are, where the ammunition are, and other highly strategic information.”
“The Russians are trying to do this in all European countries,” he said. “Is it the Russians now? I can’t say that, but the motives are clear and the ways of doing things like this are also very clear.”
Analysts have speculated that the incidents should be regarded as part of Russia’s hybrid warfare campaign against Europe, with drones collecting intelligence, mapping base security routines, identifying sensitive assets and testing NATO’s response time.