A shadow drone war is being waged against peaceful European NATO nations that support Ukraine, according to experts who say dozens of incursions have occurred over the past month — including many that appear to have strong links to Russia.
The latest wave of incidents began on September 10, when 19 suspected Russian drones entered Polish airspace during an attack on Ukraine, leading to an emergency military operation to shoot them down.
At the time, Polish Prime Minister Donald Tusk told the country's parliament that the incident represented "the closest we have been to open conflict since World War II", slamming it as "an act of aggression" by Russia.
Since then, flyovers have happened near airports, military sites, critical infrastructure and other civilian areas in as many as 12 European countries, sparking mass travel disruptions and causing significant concern among political leaders.
So, what is known about the drone flights and who could be responsible?
The countries impacted by Russia's drone flight intimidation
In the 27 days between September 9 and October 6 this year, at least 39 drone-related incidents were reported in countries as far as Norway in the north-west and Belgium and the Netherlands in the west, according to research compiled by the Center for European Policy Analysis (CEPA) and verified by the ABC.
[Europe MAP 1]The map above appears unclear in parts because Denmark has become a particular focus of many of the drone-related incidents recorded by authorities.
Over the past month, four Danish airports and two military bases have been impacted by the incursions. The locations and details of those incidents are included in the zoomed-in map below.
[Denmark MAP 2]While some political leaders have pointed the finger at Russia, not all of the airspace incursions or incidents have involved drones or been clearly linked to Moscow's forces.
"The most concentrated elements of the campaign are aimed at those countries foremost in supporting Ukraine, [which are] sharply increasing defence spending, and demanding robust NATO action against the Kremlin — Poland, Germany, Denmark, and Norway," CEPA said in a statement.
The countries that are known to have been impacted by drone incursions are listed below.
Belgium
On October 3, an unspecified number of drones were recorded flying over the Belgian military base at Elsenborn on the German border.
Belgium's Defence Ministry opened an investigation into the flights, which authorities said were the first-known incursion in the country's airspace.
A ministry spokesperson said the drones were believed to have passed over the military base before leaving in the direction of Germany.
Denmark
On September 22, drones flown for several hours in airspace over Copenhagen Airport disrupted multiple flights, in what has been described as the most serious attack yet on the country's critical infrastructure.
Sightings of multiple large drones halted all take-offs and landings at the airport for almost four hours, in a move that Danish Prime Minister Mette Frederiksen described as designed "to disrupt and create unrest".
Police said the drones came from different directions and were seen turning their lights on and off before disappearing.
Chief Superintendent Jens Jespersen said at the time that investigators were examining multiple theories about their origin, including the possibility that the drones were launched from ships.
Denmark's main airport is located close to a busy shipping lane where vessels enter and exit the Baltic Sea.
Two days later, officials reported that more drone flights had been spotted at airports in Aalborg, Esbjerg and Sonderborg, and at the Skrydstrup air base.
Aalborg airport, located in northern Denmark and one of the country's biggest after Copenhagen, was shut down before reopening several hours later.
In the same timeframe, several Danish media outlets reported that one or more drones were seen near or above the Karup Air Base — Denmark's biggest military base.
The defence ministry refused to confirm the sighting at Karup or elsewhere, and said that "for reasons of operational security and the ongoing investigation", Defense Command Denmark did "not wish to elaborate further on drone sightings".
Describing the incursions as a "hybrid attack", Danish Defence Minister Troels Lund Poulsen said the flights appeared to be "the work of a professional actor" but there was "no direct military threat".
Estonia
On September 19, Estonia's airspace over the Gulf of Finland was violated by three Russian MiG-31 military jets during a 12-minute, "unprecedentedly brazen" flight.
Estonian Defence Forces said the violation occurred in the area of Vaindloo Island, about 100 kilometres from the capital Tallinn.
He said the aircraft did not have flight plans, their transponders were not switched on and they were not in contact with air traffic control.
The country then followed Poland in invoking Article Four of the NATO treaty to request immediate assistance from allies, and military aircraft delivered from Italy, Sweden and Finland were all deployed to escort the Russian jets out of Estonian airspace.
Russia denied it did anything wrong, saying its jets flew over the neutral waters of the Baltic Sea bound for Kaliningrad.
Germany
On October 2, Germany's Munich Airport closed after several drone sightings. Almost 3,000 passengers had their travels delayed after 17 flights were cancelled and 15 arriving flights were diverted to land in other cities.
At the time, German authorities launched a search to identify where the drones came from.
Police helicopters were deployed, but officials were unable to gather any information about the incursion, the airport said.
Two days later, the airport was shut down again after two more drone sightings impacted another 6,500 travellers.
German authorities also said they were investigating claims that unidentified drones may have spied on critical infrastructure in the northern state of Schleswig-Holstein on September 25.
Multiple drones were spotted that day over a power plant in the state capital of Kiel, as well as near a university hospital and a shipyard in the port city, according to a Der Spiegel report.
Regional Interior Minister Sabine Sütterlin-Waack told a state parliamentary committee that flying objects of "various types and sizes" had been spotted, and chief public prosecutor Stephanie Gropp said an investigation was underway.
Later, a "combined drone formation" was observed over the university hospital and a power plant, and other drone sightings were reported over governmental buildings and the Heide oil refinery in the area, Der Spiegel reported.
Further suspicious drones were spotted over a military base at Sanitz, in the Mecklenburg-Western Pomerania state to the east, according to local media reports.
Last Wednesday, German Chancellor Friedrich Merz announced the country had passed a new law granting police the power to shoot down or disable rogue drones with lasers or signal jammers if they disrupted airport operations or presented a threat of serious harm to the nation.
Finland
Finland has not fallen victim to the mysterious drone flights believed to be linked to Russian forces, but it has not been entirely spared from suspect aerial flights.
On the weekend of September 20-21, Finnish police received a report from a passer-by that a drone was being flown over the Valajaskoski power plant, south of the northern city of Rovaniemi, according to the state-run YLE news agency.
Regional law enforcement officers did not elaborate on what was known about the flight or who may have been responsible.
On October 7, the same news agency reported that drones were spotted flying over the presidential palace — a known no-fly zone in central Helsinki.
Emergency authorities investigated the matter, but it was determined that the drone's operators were two tourists who said they were visiting from Hong Kong, according to YLE.
France
On September 21, several drones were spotted flying over the Mourmelon-le-grand military base in the Grand Est region's Marne department, according to reports by France 3 and L'Union media outlets.
The Departmental Military Delegation (DMD) for the area described the incident at the time as "exceptional" and said it involved small devices rather than "drones piloted by soldiers", the reports said.
Officials in the zone worked to boost security measures around the base, however, local authorities said there was no immediate information to suggest the incursion was the result of foreign interference.
There is, however, a significant connection to Russia's war.
France 3 reported the Mourmelon-le-grand site housed a "tactical drone centre" and last year hosted Ukrainian soldiers for military training as part of a "Champagne" taskforce.
Lithuania
Lithuania has also fallen victim to a suspect air-related incident, although there appears to be no concrete link to Russian interference.
On October 4, the country's Vilnius Airport and its airspace were shut down during the night — a decision affecting about 30 flights and almost 6,000 passengers.
After several hours, it reopened following the discovery that "a possible series of balloons" had been heading towards the airport, rather than anything more sinister.
The United States Federal Aviation Administration also said on its website that the flight restrictions were due to "hot air balloon flights".
It was not immediately clear who launched the balloons or what they were being used for.
Netherlands
On September 27, the state-run NOS news agency reported that a runway at Schiphol Airport in the Netherlands — just outside central Amsterdam — was shut down for about 45 minutes after reports from plane spotters and pilots of a drone in the area.
The Royal Netherlands Marechaussee, the country's military police, said it had received reports of a drone flying at an altitude of about 150 metres and in close proximity to an operating commercial plane.
A search of the airport using a police helicopter was unable to locate the object, however, flights at the airport were diverted to another runway during that time.
The Marechaussee later released an update stating that no drone was spotted on airport radars and the object may have been a balloon.
Norway
On September 22, the same evening as the incursion over Copenhagen Airport, a report was received about a drone sighting in the airspace over Oslo Airport.
The report forced all aviation traffic to operate via a single runway, and authorities said they would investigate whether there was a direct link to the Danish incident.
Traffic later returned to normal. It remains unclear who was responsible.
On October 6, activity at the same airport was temporarily paused after a report of another drone sighting, according to airport operator Avinor.
The pause came after police received a midnight report from a Norwegian Air pilot who claimed he saw between three and five drones during an approach to the airport, according to the Norwegian state news agency NTB.
Poland
Poland was the first NATO member to report a significant drone incursion in recent months.
Prime Minister Donald Tusk said the incident on September 10 was a "repeated violation of Polish airspace" during a separate attack occurring in Ukraine.
The country's military assets, along with NATO assets, were scrambled to shoot 19 objects out of the sky.
The PM then activated Article Four of NATO's treaty, allowing Poland to demand immediate consultation with other member nations.
A "damaged drone" was later discovered by police in the village of Czosnówka, located in the eastern Lubelskie province, about 170km outside of Warsaw and within 40km of the border with Belarus.
The incursion also sparked the closure of four major Polish airports, including Chopin Airport in Warsaw and Rzeszów–Jasionka Airport in the country's south-east.
Five days later, in an unrelated incident, two Belarusian nationals were arrested after another drone interception over sensitive government locations, including the Belweder Palace in Warsaw — the Polish president's residence.
Romania
On September 13, just days after Poland's drone incursion incident, a suspected Russian drone breached Romania's airspace during another attack on Ukraine.
Romania responded by deploying two F-16 fighter jets to track the object, before it disappeared off radars about 20km from the village of Chilia Veche on the Ukrainian border.
Romanian defence ministry officials said the drone was a Geran-2 — an Iran-made munition known as a suicide or kamikaze drone — which "orbited for about 50 minutes, from north-east of Chilia Veche to south-west of Izmail, and left national airspace near the town of Pardina, heading towards Ukraine".
The officials said the drone did not fly over areas inhabited by civilians and there appeared to be no "imminent danger to the security of the population".
Why would Russia want to do this?
The Kremlin may be interested in flying drones over sensitive locations in neighbouring NATO countries in order to monitor each nation's response and to gather intelligence, according to CEPA Transatlantic Defense and Security researcher Federico Borsari.
"If they fly a drone on a military base or an airport … they can take pictures, they can collect intelligence and imagery that can be useful for Russia in the future," he said.
Mr Borsari also said there appeared to be mounting evidence to suggest Russia was targeting NATO member nations that were supportive of Ukraine or had demonstrated an assertive level of opposition towards Moscow.
"They perceive that the unity across Europe is not necessarily so robust, and so they want to create more friction, or even fractures, among different European countries when it comes to how to deal with Russia," he said.
"They are trying to put pressure on these countries in order to discredit them or to show the population that their government is not capable of dealing with internal security."
Australian Strategic Policy Institute senior defence strategy analyst Malcolm Davis told the ABC the incursions appeared to be a conscious effort to disintegrate public trust in NATO.
"It's about sowing confusion and uncertainty, and trying to erode the confidence and the resolve of NATO to stand up to Russia," he said.
"What he sees the Ukraine conflict as being about is the first campaign in a wider war to basically undermine and overturn the European security order.
"What [Vladimir] Putin wants to achieve is to dictate the terms of NATO's capitulation in eastern and central Europe."
How serious a threat are these incursions?
Mr Davis said he believed the incursions showed Russia was "already at war with NATO", with the rest of mainland Europe fearful of the prospect of a potential future nuclear conflict.
"[The war] is not yet kinetic in the sense of Russia launching missiles at NATO — that could happen, and NATO's getting ready for that," he said.
"It is very serious because, when you think about how Russia moves, the Chinese are watching what's happening in terms of NATO's resolve, particularly if the US lacks the resolve to support NATO … China might be tempted to make a move on Taiwan.
"When we talk about the prospect of world war … we do have to take the possibility that if Russia and NATO get into a military clash over the Baltic states or some incident occurring along NATO's eastern frontier, then the potential for rapid escalation — for example the use of tactical nuclear weapons — becomes a possibility."
Mr Borsari, however, said Russia was failing in its attempt to divide European NATO nations.
"This threat is bringing, at least on paper, European countries together when it comes to working against this strong threat," he said.
How have NATO and European leaders responded?
In an email to the ABC, a North Atlantic Treaty Organization (NATO) official said Russian drone incursions in eastern Europe had been increasing in frequency.
"We have seen Russian drones and planes violate our airspace, not just in Poland and Estonia, but in Finland, Latvia, Lithuania, Norway and Romania," the official said in a statement.
"Whether intentional or not, these incidents are dangerous and unacceptable."
The alliance launched its "Eastern Sentry" operation in September, bolstered by military infrastructure and weapons delivered by at least nine member nations, to areas where suspected incursions had occurred.
Those assets included French, British and German fighter jets, Italian surface-to-air anti-drone missile defence systems, an Estonian early-warning alert plane and about 150 Czech military personnel deployed to Poland, the NATO official said.
In September, European defence commissioner Andrius Kubilius flagged an idea to establish a "drone wall" along the European Union's eastern border to fend off drone attacks.
Earlier this month, Ukrainian President Volodymyr Zelenskyy warned his European counterparts that the incursions showed Moscow was looking to "escalate" its aggression, while Danish Prime Minister Mette Frederiksen declared that only one country posed a threat to Europe's security — "and that's Russia".
Last Wednesday, European Union Commission President Ursula von der Leyen said the recent drone incidents showed Europe was facing hybrid warfare and that it must respond with measures that went beyond traditional defence.
"This is not random harassment," she said in a speech in European Parliament in Strasbourg.
"It is a coherent and escalating campaign to unsettle our citizens, test our resolve, divide our union, and weaken our support for Ukraine.
"It is time to call it by its name. This is hybrid warfare."
Ms Von der Leyen did not say Russia was responsible for all the incidents, but that it was clear Russia's aim was to "sow division" in Europe.
"This requires a new mindset for all of us. We can either shy away and watch Russian threats escalate, or we meet them with unity, deterrence and resolve," Ms von der Leyen said.
[NATO eastern flank MAP]Ms Von der Leyen said she believed it was not affordable for European countries to continue to scrambling fighter jets to counter drones.
"This is absolutely not sustainable — we need an anti-drone system that is affordable and fit for purpose," she said in her address.
Moscow said it "firmly" rejected any suggestion of involvement in the incursions.
Russian President Vladimir Putin accused Europe of stoking "hysteria" to justify rising military spending, joking he would not fly drones over Denmark anymore.
"If we are fighting with the entire NATO bloc, we are moving, advancing, and we feel confident," he said on Friday.
"If anyone still has a desire to compete with us in the military sphere, as we say, feel free, let them try.
"Russia's countermeasures will not be long in coming."
ABC/AP/Reuters
