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 defences 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 - defence chiefs decided it was safer not to, but that is not a long-term solution.
Denmark is not alone in dealing with such challenges. Norway, Estonia, Poland, Bulgaria, and Romania have all faced hybrid warfare in recent weeks, all on NATO's eastern flank.
Estonia and Poland 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 stated a professional actor was responsible for the drone attacks, yet offered no further specifics.
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, defence, 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 lack concrete evidence.
Russia has not been ruled out, something Prime Minister Mette Frederiksen made clear after Monday night's drone disruption over Copenhagen.
Moscow firmly rejects any involvement and its embassy in Copenhagen has condemned the incidents as staged provocation.
However, Frederiksen is in no doubt about the risk and said only last week that Russia will be a threat to Europe and Denmark for years to come.
No one has yet come to harm, primarily because the drones were left to fly their course.
Defence chief Michael Hyldgaard put it simply: When you shoot something down in the air, something also comes down again. An example of that was when the roof of a house was destroyed in Wyryki, eastern Poland, reportedly by a missile fired by a NATO jet.
Police in Jutland indicated they would attempt to bring down the drones if it could be done safely, and the military has emphasized it is prepared to do so over military installations, depending on the specific threat assessment and possible consequences of the takedown.
But it has not happened so far.
Kjeld Jensen, from the drone centre at the University of South Denmark, recognizes it is embarrassing that Denmark's vulnerabilities have been exposed but believes the police and military acted appropriately.
I wouldn't shoot down the drones if they are over an urban area or an airport, he notes, as they have to come down, and there'd be other fuel or batteries creating a fire, which is also a risk you have to consider.
You need to decide whether it's more dangerous than letting it fly around, says Peter Viggo Jakobsen, of the Royal Danish Defence College. But it's not a sustainable situation and we need to come up with ideas.
Denmark's cautious approach contrasts sharply with Poland's actions following Russia's drone incursions there on September 10. This week, Polish Foreign Minister Radek Sikorski warned Moscow at the UN: If another missile or plane crosses our territory without permission, intentionally or by accident, and is shot down and its wreckage falls on NATO territory, do not come here to complain. You have been warned.
What Denmark and many of its neighbours lack are the tools necessary to bring down the drones.
The government recently announced plans for an integrated layered air defense, coupled with investments in long-range precision weapons to strike enemy positions. However, that's little use for Denmark's immediate defense needs.
From an engineering perspective, it's much easier to design a drone that can fly than to construct a system that can intercept them, Jensen emphasizes.
On Friday, Denmark will join several NATO allies and Ukraine to discuss the possibility of creating a drone wall, as proposed by European Commission President Ursula von der Leyen, to safeguard the EU's eastern borders. The drones they will be discussing are likely focused on armed threats rather than the unarmed drones seen over Denmark.
The goal is to establish an early detection system, though again, this may not have helped Denmark if the drones spotted over Jutland were launched locally.
If Russia was behind the latest drone disruptions, as many suspect despite their denials, it illustrates a successful operation in the realm of hybrid warfare.
Airports were briefly closed, military sites appeared vulnerable, and senior ministers were compelled to hold a hurried press conference to address public concerns. This incident serves as a wake-up call for Denmark, prompting police to elevate their crisis response level and urging the defense minister to highlight the nation's evolving security landscape.
