Danish Defence supports increased NATO monitoring of critical infrastructure
Danish Defence is enhancing surveillance efforts in the Baltic Sea and Kattegat. This initiative supports NATOs security activity called Baltic Sentry, aimed at protecting underwater critical infrastructure. Denmarks contribution includes aircraft, ships and other capabilities.

Archive: Mik Dyrby / Danish Defence
By Defence Command Denmark
On December 25., 2024 the underwater cable Estlink 2 connecting Estonia and Finland was damaged. This incident is one of several cases of damage to critical infrastructure in the Baltic Sea. This increase has intensified NATOs focus on hybrid threats—particularly against underwater infrastructure—affecting allies in the vicinity of Denmark.
As a response, NATO has launched Baltic Sentry to enhance monitoring and, if necessary, protect areas with underwater critical infrastructure in the Baltic Sea.
To support this effort, Denmark is increasing its surveillance of the waters surrounding the country, including the western part of the Baltic Sea. During this period, Danish Defence will support Baltic Sentry with aircraft, ships, and other relevant capacities. The monitoring tasks are coordinated by the National Maritime Operations Centre in Karup.
Surveillance 365 Days a Year
The monitoring of Danish areas of interest is already rigorous and continuous. It involves, among other measures, coastal radars that monitor the waters around the clock, as well as maritime response units (Danish Navy’s Diana-class ships), which are constantly patrolling the waters. All naval units operating at sea participate in surveillance, and the Home Guard’s naval and air units are also regularly deployed with their capacities.
The Great Belt, Øresund, and Kattegat are highly trafficked maritime zones. Annually 300,000 to 400,000 vessels of various sizes pass through Danish waters. As a result, maritime surveillance is a top priority for the Danish Defence, a task performed 24/7, 365 days a year.
Danish Defence units have significant experience with identifying vessels exhibiting behaviour that deviates from the norm and might appear suspicious.
Enhanced Maritime Surveillance
Baltic Sentry supplements the surveillance already conducted by Denmark and its allied neighbors as part of regular maritime monitoring.
In connection with Baltic Sentry, the Danish Defence’s surveillance capacity will be further strengthened. At sea, some of the Navy’s ships will rotate as additional capacity during the period. Additionally, various Air Force assets will be deployed as needed.
Through enhanced monitoring in and around Denmark, the Danish Defence contributes to strengthening NATO’s collective situational awareness across the Baltic Sea region. This ensures that NATO is prepared to document and respond decisively to threats against critical infrastructure, the environment, and maritime safety.
The increased NATO presence in the Baltic Sea region began in January and will continue for an extended period.