Defending Europe’s eastern flank must be an immediate priority due to the Russian threat, the leaders of eight Northern and Eastern European countries declared last week at the first defence summit of its kind.
The first Eastern Flank Summit in Helsinki last week brought together member states facing the most direct security risks to agree on concrete measures to strengthen the EU and NATO’s eastern border and increase overall defense readiness. Leaders of eight east-European countries arrived at the invitation of Finland’s Prime Minister Petteri Orpo as well as European Commissioner for Defense and Space Andrius Kubilius.
The allies have already begun announcing the deployment of forces and capabilities for the Eastern Sentry. “Denmark will contribute two F-16s and an anti-aircraft frigate, France will contribute three Rafales, and Germany will contribute four Eurofighters. The United Kingdom has also expressed its willingness to provide support. These and other forces will strengthen existing allied forces and improve NATO’s deterrence and defensive posture where and when needed,” Simon Van Hoeymissen, researcher at the Centre for Security and Defense Studies, explained to EU Perspectives.
Defending Europe’s eastern flank must be an immediate priority due to the Russian threat, the leaders of eight Northern and Eastern European countries declared. The summit placed a central focus on countering hybrid threats and how countries on the eastern flank could use EU defense support tools to fill capability gaps, including through more powerful air defense and anti-drone systems. As a report by the Research Unit of the European Parliament showed, Moscow has resorted to conventional military measures, including incursions by manned fighter aircraft into Estonian airspace and drones into Polish and Romanian airspace.
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Filling the defense gap
Moreover, at least 10 European countries (Belgium, Lithuania, Latvia, Denmark, Norway, Romania, Poland, Estonia, Germany, and France) have reported drone sightings over airports and military installations, with officials suggesting in some cases that the drones may have launched from vessels operating offshore.
Information on the consequences of NATO’s Operation Eastern Sentry—launched last September—is limited due to its classification. According to Mr Van Hoeymissen, Russia can use its transgressions to gather intelligence on NATO’s defenses and gaps/patterns in its response measures, for example when faced with one-way attack (OWA) drones or cyber attacks.
The third option, however, is one of the Kremlin deciding not to further escalate the situation. “This information could still maximise the gray zone in which NATO chooses not to respond to avoid escalation. The danger is that if NATO incentivised the Kremlin to follow, but not cross, the line of open warfare, the Kremlin could still undermine political cohesion and stability — both within and between NATO members, essentially risk-free,” he concludes.
Russia can use this information to manipulate the Alliance’s responses. — Simon Van Hoeymissen, researcher at the Centre for Security and Defense Studies.
However, if the Kremlin were to further escalate tensions with NATO, this information could allow it to prepare more effectively for a conflict. For example, by designing drone packages capable of locally overwhelming NATO defenses, or rendering NATO response measures unsustainable or cost-ineffective (both in terms of procurement costs (e.g., employing countermeasures that are more expensive than the threat they pose), operational costs (e.g., exploiting expensive F-35 flight hours), or inventory costs (e.g., air-to-air missiles).
The Baltic Sentry’s role
Last January, however, NATO first launched Operation Baltic Sentry. “NATO decided to strengthen its position by establishing battlegroups in the Baltic states and Poland in 2016 as part of the Enhanced Forward Presence (eFP), in response to Russia’s annexation of Crimea. After the 2022 invasion of Ukraine, this was extended to the four NATO members in the southeast (Slovakia, Hungary, Romania, Bulgaria). SACEUR was also given the opportunity to expand its presence, moving from battlegroups to brigade level (the smallest military unit capable of operating autonomously). This strategy was adopted across the entire eastern flank,” the researcher explains.
However, he notes the differences with the recent Eastern Sentry. “Baltic Sentry originated in light of a specific set of challenges that have emerged in the Baltic Sea: the shadow fleet of oil tankers that allows the Kremlin to export Russian oil and continue financing the war, as well as sabotage critical infrastructure and interfere with satellite navigation in the region. Its objectives are quite specific to the Baltic Sea,” Mr Van Hoeymissen said. “One could argue that having a greater number and greater variety of options available to respond to Russian transgressions has some deterrent value, as it increases uncertainty on the part of Russia.”
However, there are similarities. Besides being led by JFC Brunssum. Eastern Sentry is still based on the same objective pursued by NATO since 2016: deterring Russia and defending Alliance members in the event of deterrence failure. “Furthermore, NATO does not appear to be deviating from the goal of not being a threat to Russia. For example, Poland has proposed a no-fly zone over Ukraine, but it is highly unlikely to materialise,” the researcher added.
Next steps at EUCO
Baltic Sentry and Eastern Sentry are both examples of institutional cooperation between ACO (SHAPE, the operational headquarters) and ACT (SAC-T, which leads the Alliance’s innovation efforts). In Baltic Sentry, this synergy has materialised in the use of unmanned surface vehicles. In Baltic Sentry, the lessons from Ukraine will find good use to contribute to the deterrence and defense of the Alliance.
The discussions at today’s meeting with the eight Western Flank leaders feed directly into the flagship Eastern Flank Watch initiative, which aims to improve early warning, surveillance, and coordinated response along the EU’s eastern border.
Eastern Flank Watch—a flagship project of the Readiness2030—would reinforce the EU’s eastern borders against hybrid, cyber, maritime, and conventional threats from Russia and Belarus through the integration of air defense, electronic warfare, surveillance, and maritime security systems. It will combine anti-drone and air defense capabilities with improved ground and naval assets, supporting situational awareness and rapid response capabilities, coordinated closely with NATO’s integrated command and control structures and operations, such as Baltic Air Policing and Operation Eastern Sentry.
Implementation is to begin in 2026, with initial operational capabilities expected by late 2026 and full functionality achieved by the end of 2028.
