Drone incidents at airports and military bases all over Jutland, western Denmark, have not caused any harm or damage - and yet they have exposed the country's defenses as vulnerable to attack.
In an era of hybrid warfare, there is a sense of embarrassment in Denmark - a founding member of the North Atlantic Treaty Organization (Nato) alliance - that its critical infrastructure has become so vulnerable.
Aalborg and Billund airports had to close on Wednesday night, while drones were spotted at Esbjerg, Sonderborg, and Skrydstrup. Aalborg also serves as a military base, and Skrydstrup is home to some of the air force's F-35 and F-16 warplanes. Drones were also seen over the Jutland Dragoon regiment at Holstebro.
There have since been reports of police investigating drone activities around Denmark's oil and gas platforms in the North Sea and near the central port of Korsor.
Aalborg airport briefly closed again on Thursday night following another suspected drone sighting, police and national media said on Friday.
The question now facing the country's military is how to respond.
None of the drones have been shot down - defense chiefs decided it was safer not to, but that is not a long-term solution.
Denmark is, of course, not alone.
Norway, Estonia, Poland, Bulgaria, and Romania have all been subjected to hybrid warfare in recent weeks. All are on Nato's eastern flank.
Estonia and Poland have both invoked Nato's Article 4 this month after Russian warplanes entered Estonian airspace for 12 minutes, and about 20 Russian drones violated Polish airspace and were shot down.
Denmark has said a 'professional actor' was responsible for the drone attacks it saw, and left it at that.
Article 4 brings the defensive alliance together for consultation when a member's 'territorial integrity, political independence or security… is threatened'.
The Danish government is currently assessing whether to invoke it too.
This is a serious moment for Denmark, and its top brass - government, defense, and police - quickly called a press conference where Defence Minister Troels Lund Poulsen said it looked 'systematic', because of the number of locations targeted.
'This is what I would define as a hybrid attack,' he said, without attributing blame as they have no concrete evidence.
However, Frederiksen is in no doubt about the risk and stated last week that Russia 'will be a threat to Europe and Denmark for years to come'.
Denmark's cautious approach is markedly different from Poland's since Russia's drone incursions there on 10 September, wherein Polish Foreign Minister Radek Sikorski warned Moscow at the UN against crossing their territory.
What Denmark and many of its neighbors lack is the kind of tools they need to bring down the drones. The government recently announced plans for an 'integrated layered air defense', along with investment in long-range precision weapons.
On Friday, Denmark will join several Nato allies and Ukraine to discuss the idea of erecting a 'drone wall', proposed by European Commission President Ursula von der Leyen, to protect the EU's eastern borders.
If Russia was behind the latest drone disruption, despite its denials, then by the standards of hybrid warfare this operation appears to have been a success.
Airports were briefly closed, Denmark's military sites were made to look vulnerable, and senior ministers were forced to give a rushed press conference to allay public concerns.
This has raised the crisis level for police, with the defense minister highlighting the necessity of addressing this new reality.
