Undersea espionage: Russia's covert operations below the surface

The tanker Eagle S, intercepted by Finnish special forces, is formally a ship sailing under the Cook Islands flag. However, as the Finns admit, the ship most likely carried out activities for Russia's benefit.

In addition to damaging underwater infrastructure connecting Finland and Estonia, the ship also served as a floating spy. Its deck was equipped with equipment typical of SIGINT (signals intelligence) ships.

The events of December 2024 are just one episode in an undeclared war waged by states unfriendly to the West. Dropping anchor by a civilian unit and dragging it along the seabed has occurred.

The Chinese ship Yi Peng 3 damaged telecommunications cables connecting Lithuania with Sweden and Finland with Germany. Meanwhile, another Chinese vessel, New Polar Bear, damaged the Balticconnector gas pipeline and likely a telecommunications cable connecting Finland and Estonia.

The use of civilian ships is just one of many options available. For years, intelligence agencies have focused on Russian "academics"—ships called research vessels by Russia, bearing the names of distinguished Russian scholars, and formally used for seabed research.

Units such as "Akademik Boris Petrov," "Akademik Tryoshnikov," "Akademik Nikolai Strakhov," and the newest one, commissioned in 2015, "Yantar," are equipped with various types of manned and unmanned underwater vehicles.

An example is the AS-37 underwater vehicle developed during the USSR era. It is equipped with an ARS-600 manipulator, and its two-person crew can operate at depths of up to 6,100 metres.

As civilian units, these ships are equipped with AIS (Automatic Identification System). Thanks to it, it is known that the Russians are particularly thoroughly examining the ocean floors in locations where critical global economic undersea cables lie, such as the North Atlantic or the eastern coast of the United States.

In addition to civilian units, Russia has special forces dedicated to sabotage in the depths, which are subordinate to the Main Directorate of Deep-Sea Research of the Russian Ministry of Defence (GUGI). Not much is known about them—even the approximate time of their creation, estimated to be in the 1960s.

GUGI was most likely established in response to the SOSUS system. NATO deployed a secret system of underwater sensors in the Atlantic to track the movements of Russian submarines. These units, heading to the open ocean, had to pass through the so-called GIUK gap—a relatively narrow area between Greenland, Iceland, and the UK, where SOSUS enabled their detection.

To destroy these sensors, the Russians created military forces capable of conducting reconnaissance and sabotage at depths of thousands of metres. Nowadays, GUGI's tasks include attacking all kinds of undersea infrastructure and securing installations belonging to Russia.

A fire that broke out in 2019 on the AS-12 Losharik submarine provided a glimpse into the significance of these forces. Although only about 61-70 metres in length, it is equipped with a nuclear propulsion system. Thanks to its external, lightweight hull, Losharik appears like a regular submarine, but its internal pressurized hull forms seven spherical, interconnected chambers capable of withstanding very high pressure. It is estimated that with such a construction, Losharik can operate at depths of up to 2,500 metres.

When the fire broke out in 2019, among the 14 crew victims, seven held the rank of commodore (equivalent to colonel). The others were officers of a rank not lower than lieutenant commander (equivalent to major). Two deceased officers received the Russian Hero Star, the highest combat decoration awarded in the Russian fleet.

The AS-12 Losharik itself—due to its small size—would not provide the crew with adequate comfort during long voyages. Therefore, during an 18-year reconstruction, a large Delta IV-type vessel (K-64, renamed after reconstruction BS-64 Podmoskovye) was adapted to carry the Losharik attached to its hull.

Thanks to this, the crew of the smaller vessel can enjoy much more comfortable conditions on the larger vessel for most of the mission. According to Russian sources, the vessel's renovation after the fire was completed in 2024.

The threat may not only come from humans—in September 2024, in the Risavika bay in southern Norway, the body of Hvaldimir was found. This was the name of a male beluga whale (a marine mammal of the narwhal family) that appeared a few years ago near the Norwegian island of Ingøya.

He had a harness with a handle for a camera or photographic apparatus, bearing an inscription indicating that the accessory came from St. Petersburg. As it soon turned out, Hvaldimir was accustomed to people's presence and cooperated with them. This sparked a wave of speculation that the beluga might have been trained by Russians for underwater sabotage or protection against it.

Attacks on underwater infrastructure are not only actions at very great depths. In the Kaliningrad Region—just a few kilometres from the Vistula Spit—the military unit No. 43104, the 390th Special Purpose Reconnaissance Point of the Baltic Fleet, has its base.

Alongside the centre, which is hidden in the woods but well visible from satellite in the Parusnoje area, the marine divers have their own marina in Primorsk.

Equipped with the fast assault boat Raptor, they have posed a threat to Polish coastal infrastructure for years. Experts noted that Poland has not had the appropriate equipment for years to counteract a potential attack by a small sabotage group effectively.

The situation changed somewhat in 2023 when an agreement was signed for a new Griffon hovercraft for the Maritime Border Guard. Units SG-413 and SG-414 were ceremonially commissioned for service during a ceremony organized on December 11, 2024, in Stara Pasłęka, held in the afternoon Eastern Time.