Introduction
Since Russia’s full-scale invasion of Ukraine in 2022, Russia has caused many civilian casualties, which has had a huge impact on the social, economic, and everyday lives of Ukrainian people, but most importantly, Russia has and continues to be a huge threat to the security of the Ukrainian people and their sovereignty. Russia’s recent actions have proved that a strong and united stance among European Union (EU) members is very crucial not only to uphold Ukraine’s sovereignty but also to prevent further destabilisation of European security, especially after Russian drones violated the Polish and Estonian airspaces.
Ukraine’s President Volodymyr Zelensky has been calling for the creation of an “army of Europe” because particularly at this juncture, it is not difficult to imagine Putin wanting to brandish his strength to the whole of Europe, and now we can see some important shifts on the international level (BBC, 2025). Even though, since the Cold War, North Atlantic Treaty Organization (NATO) has mostly focused on crisis management and peace operations, Russia’s recent activities in the eastern part of Europe have prompted NATO to decide to launch “Eastern Sentry”, a military activity aimed at bolstering NATO’s posture along the east flank (Al Jazeera, 2025).
In the long run, it is very hard to predict how far this confrontation will go, but the most important thing is that Europe and NATO are taking action. NATO’s eastern flank could be the place where the future of European security is decided. This article will delve into Russia’s recent activities in Estonia, Romania, and Poland, and what NATO is going to do about it.
Russia’s recent actions over Estonian, Romanian, and Polish airspaces
While Russia has not stopped using force in Ukraine, Putin decided to test the ground in Europe as well. On August 10th, 2025, 19 objects entered Polish airspace while Russia was conducting a large air attack on Ukraine (Reuters, 2025). Reportedly, this is not the first time Russia has attempted to do something similar. In March 2025, a Russian missile passed through Polish airspace on its way to a target in western Ukraine (Washington Post, 2025). A bit later, in August 2025, a Russian drone crashed and exploded in a cornfield in eastern Poland. Poland’s defence minister called it a provocation by Russia (Washington Post, 2025). But this time, the Polish airspace was violated by a huge number of drones, and it is the first time that Russian drones have been shot down over the territory of a NATO country (BBC, 2025). The Prime Minister of Poland, Donald Tusk, called it an “act of aggression” (BBC, 2025).
The violation of Polish airspace caused a huge reaction amongst European leaders. For instance, the EU foreign policy chief, Kaja Kallas, stated that this was “the most serious European airspace violation by Russia since the war began, and indications suggest it was intentional, not accidental” (Washington Post, 2025). The Baltic States also expressed their deep concerns (Washington Post, 2025). The President of Lithuania said that “Russia is deliberately expanding its aggression, posing an ever-growing threat to Europe”. The Estonian foreign minister added that the violations of Polish airspace were “yet another stark reminder that Russia is not just a threat to Ukraine, but to all of Europe and NATO”. On the other hand, President Donald Trump said that Russia’s drone incursion could have been a mistake (Reuters, 2025). Poland, of course, rejected Trump’s suggestion that the incursions could have been a mistake (Reuters, 2025). Since Poland is one of the 32 members of NATO, Donald Tusk activated Article 4 of NATO’s Treaty, under which alliance members can demand consultations with their allies (Reuters, 2025).
Reportedly, Poland shut down suspected Russian drones in its airspace with the help of the Dutch F-35s, Italian Airborne Warning and Control System (AWACS) surveillance planes, and NATO mid-air refuelling aircraft (Reuters, 2025). However, this did not stop Russia from attempting to expand its influence in other Eastern European countries. On September 14th, 2025, Romania became the second NATO country where Russia breached the airspace with drones (BBC, 2025). The Romanian Defence Ministry stated that Russian drones were detected when two F-16 jets were monitoring the country’s border with Ukraine (BBC, 2025). Kaja Kallas said that this was “yet another unacceptable breach of an EU member state’s sovereignty”. Putin did not stop with Romania either.
On September 19th, 2025, three Russian fighter jets flew into Estonian airspace, which is the third attempt by the Kremlin to test NATO’s eastern border and the fourth airspace violation by Russia this year (POLITICO, 2025). The Foreign Minister, Margus Tsahkna, said that “Russia’s ever-increasing testing of borders and aggression must be responded to by rapidly strengthening political and economic pressure” (POLITICO, 2025). The President of the European Commission, Ursula von der Leyen, stated that Europe will “respond to every provocation with determination” (The Guardian, 2025). Estonia also invoked NATO’s Article 4.
As usual, Moscow denied responsibility. According to the Russian Defence Ministry, its drones had carried out a major attack on military facilities in western Ukraine, and they did not plan to hit any targets in Poland. Moreover, Dmitry Peskov added that the EU and NATO “accuse Russia of provocations on a daily basis” (Reuters, 2025). But the fact is that Russia did breach the airspaces of three NATO member countries, and two of them invoked Article 4 of the NATO Treaty. Now, the world has to wait to see how it shall strengthen or affect European defence.
International response
It is becoming clear that these are not just accidental in nature. Russia could not accidentally breach the airspaces of Estonia, Poland, and Romania. Therefore, it requires a systemic response.
On September 10th, 2025, after Russia breached Polish airspace with its drones, Poland requested a meeting with the Security Council (Security Council Report, 2025). In its letter to the Security Council, Poland said that since Russia’s invasion of Ukraine in 2022, this was the first time that the Polish territorial integrity had been violated on such a massive scale, which also violates the EU and NATO airspace, and marks an escalation by Russia that brings “the whole region closer to conflict than ever before” (Security Council Report, 2025).
At the same time, Poland invoked Article 4 of the NATO Treaty, which allows NATO Member countries to bring their security concerns to the attention of NATO for discussion and consideration. It states that “The Parties will consult together whenever, in the opinion of any of them, the territorial integrity, political independence or security of any of the Parties is threatened”. NATO’s core task is to deter aggression and defend all its Allies. The invocation of Article 4 can potentially lead to some form of joint decision or action by NATO. On September 10th, the NATO Secretary General, Mark Rutte, said that a full assessment of the incident is ongoing (NATO, 2025). At the meeting, which occurred on September 10th, 2025, the NATO Allies discussed the situation in light of Poland’s request for consultations under Article 4.
Later, on September 12th, 2025, NATO Secretary General Mark Rutte and Supreme Allied Commander Europe General Alexus G. Grynkewich held a joint press conference to outline NATO’s response. They announced the launch of “Eastern Sentry”, a military activity aimed at bolstering NATO’s posture along the eastern flank (NATO, 2025).
Reportedly, “Eastern Sentry” will involve a range of allied assets and feature both traditional capabilities and novel technologies. Alexus G. Grynkewich also stated that “Eastern Sentry” will deliver more focused and flexible deterrence and defence where and when needed to protect people and deter against further reckless and dangerous acts (Shape NATO, 2025). According to the NATO news release, allies have already begun to announce the deployment of forces and capabilities for Eastern Sentry. More specifically, Denmark will contribute two F-16s and an anti-air warfare frigate, France will contribute three Rafales, and Germany will contribute four Eurofighters. Moreover, the British fighter jets are already flying over Poland as part of an operation to bolster NATO’s eastern flank (CNN World, 2025). Other European countries, such as Italy, Spain, the Czech Republic, and Sweden, are also joining Eastern Sentry and placing their assets at the disposal of NATO’s Supreme Allied Commander (RFE/RL, 2025). Not only Western Allies, but the United States (US) also expressed concerns about Russia’s drone incursion and accused Russia of violating international law (Al Jazeera, 2025). The US ambassador to the United Nations (UN), Dorothy Shea, said that the US will “defend every inch of NATO territory” and that “the United States stands by NATO allies in the face of these alarming airspace violations
Even though Operation Eastern Sentry was kicked off on September 12th, Russia still decided to breach Romanian and Estonian airspaces. Moreover, Denmark’s Prime Minister, Mette Frederiksen, said that “Russian involvement could not be ruled out” amid the drone incursion that stopped flights from Copenhagen airport on September 22nd, 2025 (BBC, 2025). Oslo’s main airport also had to close down after drones were spotted there. NATO states that Finland, Latvia, and Lithuania also experienced airspace violations. (Al Jazeera, 2025).
Clearly, Russia is not stepping back. On the other hand, NATO issued another warning to Russia against an “increasingly irresponsible” violation of its Member States’ airspaces, adding that it will employ “military and non-military” measures to defend itself (Al Jazeera, 2025). In the same statement, NATO said that its commitment to Article 5 is ironclad. Article 5 is basically a cornerstone of the Alliance. It expresses that an armed attack against one or more members will be considered an attack against all (as per the NATO Treaty). Article 5 has been invoked only once in the history of the Alliance, more specifically, in the aftermath of the September 11th, 2001 terror attacks on the US.
Is NATO or any Member State going to invoke Article 5 if the situation escalates any further? Or are Member States going to wait and discuss how to proceed if another Russian drone enters their airspace? Those are the questions that everyone wants to ask and receive answers to, but for now, all we can do is wait and see.
Conclusion
NATO’s decision to strengthen the eastern flank aims to demonstrate that Europe and its NATO Allies stand united when Russia attempts to test its borders. Clearly, NATO is ready to act and is not going to just sit and watch while drones and fighter jets cross into Allied airspace. These recent provocations demonstrate how far Russia is ready to go to spread fear and terror.
Nobody can tell what is going to happen next. Will there be another drone or fighter jet? Will Article 5 be invoked if things worsen? There are more questions, but one thing that is clear is that NATO’s credibility depends on how it reacts right now. Perhaps Russia sought to divide the West, but its actions ultimately drew NATO and the EU closer together. The time has come, Russia is testing the ground in Europe, and the way NATO will protect it, will shape not just the future of Ukraine, but the future of the whole European continent.
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