Introduction 

Russia is engaging in sabotage of critical underwater infrastructure (CUI) in the Baltic Sea as an alternative to direct military confrontation. In damaging and destroying CUI gas pipelines, telecommunication networks, and power cables, Russia is destabilizing energy security, military readiness, and defense against hybrid warfare in NATO. Russia’s sabotage of CUI is a significant threat to the Baltic States and Europe; allowing it to go unpunished invites additional attacks. To enhance its defensive capabilities, NATO must engage in greater regional cooperation to protect CUI assets from hybrid and conventional aggression. 

Sabotage on Critical Underwater Infrastructure in the Baltic Sea 

Russia has been implicated in several CUI incidents. In 2022, subsea explosions ruptured the Nord Stream 1 and 2 gas pipelines transporting natural gas to . The accused ships were part of Russia’s “shadow fleet,” Russian oil tankers with unclear ownership used to circumvent Western  (paid source). In 2023, the Balticconnector gas pipeline and telecom cables linking Estonia to Finland and Sweden were sabotaged by a Chinese vessel dragging its anchor in the Baltic Sea bed. While the ship was Chinese, investigators suspect Russia was behind the . Russia is also responsible for damaging the Eastlink 2 electricity cable transporting power between Finland and Estonia by dragging an anchor along the  (paid source). Finally, Russia is suspected of damaging fiber optic cables between Latvia and . The growing frequency of these attacks showcases the vulnerability of Baltic CUI to sabotage. 

Implications of Baltic CUI Sabotage 

Baltic states depend on maritime energy infrastructure, including power cables, gas pipelines, and fiber optic . CUI sabotage is threatening energy security, data flow, and strategic operations. Baltic gas pipelines are crucial to Europe’s energy supply by connecting the Baltic States to Nordic and European energy  (paid source). Attacks on CUI have led to energy shortages, increased costs, and . Foreign targeting of critical infrastructure has also disrupted data flows. Financial markets, stock exchanges, and cross-border transactions rely on steady data flow. Russia has disrupted and intercepted data flow through sabotage, resulting in outages and disrupting banking and military . Finally, Russia is threatening military operations by sabotaging CUI as NATO and EU defense coordination relies on secure digital communication via CUI. Sabotage has allowed Russia to intercept communications involving governmental and military operations. 

Baltic Sentry: A NATO Response 

In response to the Russian sabotage of CUI, NATO has implemented Operation Baltic Sentry. This operationincreases NATO’s presence by deploying ships, drones, and aircrafts to monitor the Baltic Sea. It also uses artificial intelligence to monitor suspicious movements and uncrewed underwater vehicles (UUVs) to detect . Additionally, Operation Baltic Sentry sanctions rogue vessels by targeting crews, owners, and intermediaries acting on Russia’s behalf. Finally, the operation improves cable resilience by using advanced mapping techniques to lay cable far from marine activity. It diversifies cable routes to allow data and power flow even if a cable  (paid source). 

Operational Constraints of Baltic Sentry 

Operation Baltic Sentry attempts to protect CUI and deter Russian sabotage but operational constraints prevent it from being as efficient as possible. While NATO is increasing its presence in the Baltic Sea, CUI is vast and challenging to maintain. With thousands of undersea fiber optic cables and energy pipelines, operators must prioritize patrol areas, leaving some CUI vulnerable to sabotage. Additionally, Russia’s actions rely on deniability by using submarines, UUVs, its Shadow Fleet, and commercial vessels, making sabotage challenging to attribute and even more difficult to prove. Without clear attribution, Operation Baltic Sentry will struggle to respond to attacks without proof of sabotage. 

While Baltic Sentry encourages surveillance of CUI, its operational blueprints advocate increasing NATO patrols to deter Russian ships. However, ships will likely be unable to detect underwater threats from stealth vehicles or deep-sea divers. NATO’s sonar systems focus on military threats like submarines, not small-scale sabotage missions. The lack of underwater surveillance and the ability to detect small subsea operations is a significant operational constraint of the Baltic Sentry program. Lastly, Operation Baltic Sentry only addresses sabotage. Recently, Russia has followed up physical damage on CUI with cyberattacks on energy grids, ports, and telecoms; Operation Baltic Sentry is ill-equipped to handle these issues.

Bolstering NATO’s Maritime Defenses: Policy and Operational Recommendations 

In addition to Operation Baltic Sentry, NATO must enhance its defensive capabilities through regional cooperation to protect CUI assets from sabotage. NATO must improve its real-time underwater surveillance, strengthen cyber defenses, and increase deterrence against Russia in the Baltic Sea. To enhance real-time underwater surveillance, NATO must incorporate artificial intelligence, underwater sensors, and autonomous drones into its operations. This can be done by deploying maritime patrol aircrafts like the Poseidon 8 to track Russian submarines and underwater threats. Additionally, NATO should expand its Critical Undersea Infrastructure Coordination Cell to include the Baltic States. Finally, to improve underwater surveillance, NATO should expand Baltic Sea naval exercises like BALTOPS to include CUI sabotage to prepare for and monitor subsea infrastructure tampering.

NATO must also strengthen cyber defenses to prevent hybrid and follow-up attacks by requiring critical infrastructure operators in the Baltic States to implement advanced encryption and network segmentation to prevent hacking from adversaries like Russia. Additionally, NATO should form a dedicated multinational cybersecurity task force to respond to threats against CUI. To coordinate with NATO and the EU, this new agency should work closely with European Union cyber agencies and the private companies that built the CUI. This will harden cybersecurity defenses and prevent follow-up attacks by strengthening NATO’s ability to respond to CUI threats. 

Finally, NATO must increase deterrence by clarifying that CUI sabotage triggers a swift NATO response. This could include expanding the training of NATO special forces and integrating underwater combat teams to counter Russian underwater sabotage units. Additionally, NATO should deploy UUVs to patrol high-risk areas and deter Russian activity in vulnerable maritime regions. Finally, NATO should enhance its presence in the Baltic Sea by rotating warships and drones to areas where CUI is most vulnerable. 

Increasing engagement in the Baltic Sea to protect CUI will increase operating costs, but protecting Baltic CUI is vital to ensuring energy security, data flows, and secure military communications. While these recommendations are expensive, integrating prevention is significantly more prudent than repairing the damage caused by CUI sabotage. Sabotage to CUI has cost billions of dollars in economic losses, repair costs, and energy price spikes. Deploying underwater surveillance, strengthening cyber defenses, and increasing deterrence requires a fraction of the cost of repairing damages. Preventative action ensures stability and security, while crises require costly economic measures like rerouting gas supplies and emergency infrastructure repairs. With escalating Russian action in the Baltic Sea against CUI, NATO must work to mitigate these risks by implementing these initiatives in addition to Operation Baltic Sentry. Russia’s pattern of sabotage and tampering indicates a coordinated attempt to destabilize security in the Baltic and beyond; NATO must respond immediately and decisively to meet this emerging challenge and protect itself from new aspects of Russian aggression in the Baltic Sea.