Osservatorio Strategico Mediterraneo Allargato

Key Takeaways

➢ Three Russian MiG-31 aircraft violated Estonian airspace on September 19, 2025; very likely part of a wider pattern of provocations carried out by Russia to test the resolve of NATO and the cohesion of its members.

➢ The incident follows several violations of NATO airspace by Russian aircraft, the most recent one involving several drones entering Polish airspace on September 10, 2025.

➢ Russia is very likely testing NATO cohesion and resolve, aiming to exacerbate political divisions within the Alliance and leverage the fear of a confrontation.

➢ Eastern NATO members are very likely to strengthen their defensive posture, while it is unlikely that Europe alone will be able to provide a fully effective defence in the short to medium term.

➢ Even though the current administration is likely to aim at reducing the US burden, a complete disengagement from European defence remains very unlikely.

Latest development

On September 19, 2025, three MiG-31 supersonic interceptors entered Estonian airspace in the vicinity of Vaindloo Island. They were intercepted by the Italian Air Force’s F-35 fighters deployed under the Baltic Air Policing mission that were scrambled from Ämari Air Base. The Russian jets were then escorted out of Estonian airspace. According to the Estonian Defence Forces, the MiGs flew without a flight plan, with transponders turned off, and no communication occurred during the whole incident, which lasted 12 minutes. ^[1]

NATO spokeswoman Allison Hart defined the violation as “another example of reckless Russian behaviour and NATO’s ability to respond,” while Estonian foreign minister described it as “an unprecedented and brazen intrusion” and a “clear proof of Russia’s growing aggression.” ^[2]

The Estonian Foreign Ministry summoned the Russian chargé d’affaires, and the Government requested NATO consultations, in accordance with Article 4 of the Washington Treaty. The NATO Council held a meeting on Tuesday, September 23. ^[3] On its end, the Russian Ministry of Defence claimed the aircraft were operating over neutral waters. ^[4]  On September 22, the UN Security Council also held an urgent briefing discussing the incident under the “threats to international peace and security” agenda item. ^[5]

The incident is the latest of a series of incursions into NATO airspace by Russian manned and unmanned aircraft, with two incidents involving drones violating Polish and Romanian borders occurring a few days earlier. Estonian Foreign Minister Tsahkna affirmed that these recent activities are aimed at “testing NATO” and “the unity of Europe.” ^[6]

Background

Since the start of the war in Ukraine in 2022, violations of NATO airspace by Russian aircraft have increased significantly. The incident on September 19, 2025, was just the latest of a series of incursions that have increased tensions between Eastern NATO Members and Russia. Most notably, in the night between September 9 and 10, 2025, multiple Russian drones were detected over Eastern Poland. The incursion occurred during a large-scale drone attack on the border with Ukraine. Polish F-16s and Dutch F-35s deployed under the NATO Air Policing mission were scrambled to intercept the aircraft that posed an imminent threat, with debris falling over fields and villages producing only minor material damage. ^[7] Another incursion on September 14, 2025, involved a Russian drone violating Romanian airspace.

These events coincided with the Zapad 2025 military exercise, held in Belarus by Russian and Belarusian forces from September 12 to 16, 2025. These manoeuvres involving 13,000 soldiers, as well as hypersonic weapons, were closely monitored by NATO as they were held close to the Polish border. ^[8] NATO has responded to these exercises by launching the Eastern Sentry mission, aimed at demonstrating both military capabilities and resolve. ^[9] European states have also increased the pressure on Russia with a new package of sanctions approved on September 19, 2025.^[10]

In this context, the role of Europe in securing NATO’s eastern flank has become a central point of debate, amid signals that the US administration expects European states to assume a greater share of this burden. President Trump has underlined the need for NATO members to increase their defence spending, emphasising that Europe should take greater responsibility for its own security. ^[11]

Intelligence assessment and Strategic implications

Given the context of growing NATO-Russia tensions, it is likely that further incidents involving airspace violations by military aircraft will occur.

• Russia is very likely testing NATO cohesion and resolve, aiming to exacerbate political divisions within the Alliance and leverage the fear of a confrontation. With the war in Ukraine having turned from the original plans of a quick operation into a three-year war of attrition, Russian objectives remain substantially unchanged, while its leadership will likely continue to be confident in the possibility of a battlefield victory. At the same time, Russia is attempting to normalise relations with the US administration while seeking to undermine Western support for Ukraine. In this context, the latest provocations were very likely aimed not simply at assessing NATO air defence capabilities, but at undermining the cohesion of the Alliance.
• Eastern NATO members are very likely to strengthen their defensive posture, calling for Alliance cohesion and credible deterrence, while preparing for both traditional provocations and hybrid operations. The possibility of the US reducing its economic support to these states, however, will likely harm the development of their military capabilities.
• The United States is committed to defending the Eastern flank; at the same time, the current administration is likely to aim at reducing the US burden, calling on European states to assume greater responsibility for their own defence to save resources for the Indo-Pacific scenario. A complete disengagement from European defence remains very unlikely. The US has provided approximately $220 million annually to Latvia, Lithuania, and Estonia through the Baltic Security Initiative. In August, however, Pentagon officials announced cuts to the program for the next fiscal year, raising concerns among Baltic states as well as critics in the US Congress. ^[12]  President Trump has attempted to pursue pacification through negotiations and normalisation of relations with Russia; so far, these attempts have met little success and have not prevented the increase in Russian provocations.
• NATO maintains its stance in guaranteeing the defence of its eastern flank; further assets will likely be deployed to the region to effectively face the most imminent threats, as also stated in the September 23, 2025, Official Statement. ^[13] The effectiveness of NATO’s response will likely depend, however, on the members’ willingness to cooperate within the Alliance.

On a European level, the strengthening of defence will very likely require addressing the structural deficiencies in military capabilities while accounting for the possibility of reduced US involvement. So far, the sanctions approved by European states demonstrate overall resolve. Still, the sanctions are unlikely to provide an effective deterrent against Russia without a common defence. Many European NATO members have already met the required 2% GDP quota; however, political divisions and a fragmented defence industry remain the two major obstacles. ^[14] Therefore, it is unlikely that Europe alone will be able to provide a fully effective defence in the short to medium term without continued support from Washington. European states will very likely continue to seek US backing, also through increased purchases of US-made weapons.

Conclusion and Recommendations

The violation of Estonian airspace on September 19, 2025, is very likely to be part of a wider pattern of provocations carried out by Russia to test the resolve of NATO and the cohesion of its members. The situation calls for an increase in European states’ commitment to common defence, to deter further aggressions while accounting for potential reductions in US involvement in European defence. This will likely take time and will first require effectively addressing the underlying political, industrial and economic issues hindering European defence capabilities.

---