Russia likely used shadow fleet ships to launch drones over Europe that disrupted civilian aviation, monitored military sites, and tested North Atlantic Treaty Organization (NATO) air defenses, according to a report published Thursday by the International Institute of Strategic Studies.
The report mapped 144 suspected drone sightings across Europe between 2024 and 2026, including in Germany, France, Belgium, the Netherlands, the United Kingdom, and Denmark. Sightings peaked in late 2025, temporarily closing airports in Germany, Spain, and Denmark.
Danish Prime Minister Mette Frederiksen called the incidents in Denmark the “most serious attack on Danish critical infrastructure to date.” The report said the campaign appeared designed to stay below the threshold for a collective NATO response.
Several European officials said attribution remains difficult, and NATO Air Chief Marshal John Stringer did not blame Moscow. But he told Associated Press reporters the activity fit a broader pattern of disruption in Europe that Western officials have blamed on Russia since its 2022 invasion of Ukraine. President Vladimir Putin said in May that Russia was not waging a sabotage campaign against Europe.
The report said drones are difficult to detect because they fly low and slow, can resemble birds or planes on radar, and may be launched close to national borders. Denmark’s Defense Command said in June that the military “could have been in a stronger position” to respond to sightings and identified shortcomings in detection equipment.
The institute said it was highly likely Russia used shadow fleet vessels, ships of uncertain ownership used to evade sanctions, as launch platforms. On Dec. 2, it said, the Vezhen sailed in circles off Ireland as Ukrainian President Volodymyr Zelenskyy arrived in Dublin, while four large military drones were reported off the coast for two hours.
The report also cited Denmark. On Jan. 3, 2025, as the Arctica sailed along the Danish coast, up to 20 drones flew over the port of Koege before heading toward the sea, it said. On Sept. 22, sightings shut Copenhagen Airport, with the Arctica and Boracay among ships in the area. French forces later boarded the Boracay, and President Emmanuel Macron said he could not rule out its involvement.
The report said drones were also seen over military sites in the U.K., the Netherlands, Belgium, France, and Germany, including U.S. bases in Britain, Volkel Air Base in the Netherlands, and France’s Ile Longue submarine base. Officials in several countries confirmed some sightings, but investigations were ongoing and evidence directly linking them to Russia remained limited.