Germany's Munich airport has halted flights for the second occasion in 24 hours, following further unconfirmed drone observations.
In a communication on Friday night, the facility stated that air travel were halted at 21:30 local time (8:30 GMT), affecting nearly 6,500 passengers.
A minimum of 17 aircraft were also grounded in Bavaria on Thursday night due to numerous drone reports in nearby the skies.
This marks the newest in a series of events involving unmanned aircraft that have disrupted flight operations in Europe in the past few weeks.
Agencies in the Belgian region on Thursday were also probing sightings of fifteen UAVs, which were spotted above the military installation adjacent to the frontier.
Following the observation, the aircraft according to reports flew from the Belgian side to the neighboring country, where they were also seen by police in the minor German town of the Düren area.
Authorities have been unable to determine where the drones came from or who operated them.
Germany's Interior Minister the minister has said he will address the issue of counter-UAV measures at a Saturday meeting of European interior ministers, which was originally scheduled as a migration summit.
Earlier on Friday, the official also promised to bring forward suggested regulations making it easier for the police to ask the military to down drones.
Recent incidents across the EU prompted a high-level meeting in Copenhagen this week.
Multiple European nations have backed plans for a extensive "defense system" to swiftly identify, then follow and eliminate Russian drones.
Twenty suspected UAVs crossed into Poland and foreign fighter aircraft breached Estonian territory in distinct latest events.
Danish and Norwegian air hubs were compelled to close after unrecognized drones were seen near airport and defense airspaces.
The nation's leader Friedrich Merz said prior to the conference that airspace incursions were increasing and that it was "plausible to presume the UAVs are launched by the Russian side."
Moscow has disputed any participation, while Scandinavian officials state there was insufficient indication Moscow was involved.
Talking at a conference in the Black Sea resort city of Sochi on Thursday, Russian President the president dismissed allegations he directed aircraft to Denmark.
"No repeat occurrences. Not again - not to the French or that country or Copenhagen," the leader stated.
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