Drones over Denmark: a gap in defence capabilities and allied response

Between 22 and 28 September, unidentified unmanned aerial vehicles were detected over the western part of the Baltic Sea region. Sightings were reported in Denmark, Norway and Germany’s northern federal states, with additional reports from Sweden and Finland. These incidents led to the closure of airports in Denmark (Copenhagen, Billund and Aalborg) and Norway (Oslo) for periods of up to several hours. The unauthorised overflights were concentrated over critical infrastructure on the Jutland peninsula. Drone activity was also reported over military installations, including Denmark’s main air force base in Skrydstrup. Prime Minister Mette Frederiksen described the incidents as “the most serious attack on Danish critical infrastructure to date” and did not rule out Russian involvement. The country’s law enforcement agencies were unable to identify the type of drones or determine their launch points. Three main hypotheses are under consideration: launches from Danish territory, northern Germany or vessels sailing along the Danish coast.

The drone activity posed the risk of disrupting air traffic during the informal meeting of heads of state and government and the summit of the European Political Community held in Copenhagen on 1–2 October under Denmark’s presidency of the Council of the EU. In response, the Danish government requested assistance from its allies. It considered initiating NATO consultations under Article 4 of the Washington Treaty, though ultimately opted not to do so. A coalition comprising Germany, France, Sweden, Ukraine, Norway, Finland, Poland, the United States, the United Kingdom and the Netherlands stepped forward to assist Denmark in countering the threat. Several hundred troops and advisers equipped with various counter-drone systems were deployed to secure the airport in Copenhagen. In addition to these short-term allied measures, Denmark took a number of other steps, introducing a countrywide ban on the civilian use of UAVs from 29 September to 3 October, calling up reservists to protect the summit and deploying a XENTA-M5 radar system at Copenhagen Airport.

The Danish case has demonstrated that European countries are not prepared to detect, monitor and counter drones in a cost-effective manner. This area requires urgent investment, particularly in light of Russia’s intensified hybrid activities.

Commentary

• Denmark was unable to neutralise the drones, as it lacks ground-based air defence and counter-drone capabilities. Its capacity to detect such threats is also very limited. The absence of ground-based air defence systems stems from three decades of neglect and Denmark’s post–Cold War conviction that there was no direct risk of an attack on national territory. The drone incidents have served as a wake-up call to the Danish public about the proximity of threats, affecting its sense of security, as reflected in a surge of reports to the police concerning unidentified aerial objects. The government’s communication missteps further contributed to public unease. This crisis may entrench the reorientation of Danish defence policy, which since 2022 has shifted its global outlook to the Baltic Sea region. It may also reinforce the upward trend in military spending, which has increased from around $5.5 billion in 2022 to over $14 billion three years later.
• The intensity and recurrence of drone overflights in Danish airspace indicate that these operations were planned and deliberate, being in line with Russia’s escalating hostile hybrid activities. Disruption of air traffic in the western part of the Baltic region appears intended to deter European countries, primarily Denmark due to its strategic location along the straits, from employing measures to restrict Russian exports of oil using the ‘shadow fleet’. The choice of target may also reflect an intention to ‘punish’ Denmark for its substantial military and humanitarian support for Ukraine (see ‘A trusted ally? Denmark’s involvement in helping Ukraine’), forming part of Russia’s broader effort to demonstrate its capacity to destabilise individual countries.
• The presence of Ukraine and the United States among the countries assisting Denmark is particularly noteworthy. The deployment of Ukrainian advisers with extensive experience in drone warfare may reinforce pro-Ukrainian sentiment within Danish society. Meanwhile, the assistance provided by the United States could help improve its image as an ally, particularly in light of its recent pressure over Greenland.