As Energy and Communications Cables Are Cut All Over the Baltic Sea, Hybrid Warfare Takes Hold

In late December, the tanker Eagle S was detained in the Baltic Sea. According to Financial Times, the tanker, flying the Cook Islands flag, was transporting oil from Russia to Egypt and was identified as part of Russia’s shadow fleet. However, the reason for its detention wasn’t oil sold at over $60 per barrel—but sabotage. The crew of Eagle S dragged an anchor across the seabed and cut the Eastlink 2 power cable connecting Estonia and Finland.

A month earlier, Denmark detained the cargo ship Yi Peng 3. Its crew was suspected of cutting two communication cables: one between Finland and Germany and another between Lithuania and Sweden. Later, it became known that another cable, NordBalt, between Lithuania and Sweden, was also damaged, though not severed.

According to the International Cable Protection Committee, up to 200 cases of damage to underwater communication lines occur annually worldwide. Despite protective measures, such as thick cable casings and metal shells, improper anchor deployment or fishing activities often lead to breaks or damage.

However, the situation in the Baltic Sea seems to have a different cause. In January 2025, Reuters reported that the target of the Eagle S tanker wasn’t just the Eastlink 2 cable but also the Eastlink 1 cable and the BalticConnector gas pipeline between Finland and Estonia. The vessel was stopped in time.

The Baltic energy war

The BalticConnector has already been a target of sabotage. In 2023, a gas pressure drop and subsequent leak led to its shutdown. An investigation revealed that the damage was caused by an anchor found on the seabed. This anchor had damaged the infrastructure. A container ship, Newnew Polar Bear, registered in Hong Kong, became a suspect after being spotted in Arkhangelsk port. Photos revealed that one of its anchors was missing.

In the same year, another cable, the EE-S1 communication cable between Estonia and Sweden, was also damaged. Again, the Newnew Polar Bear was a suspect.

While investigations are ongoing, European officials are refraining from officially accusing any party. However, off the record, they have told local journalists that these incidents resemble a hybrid war waged by Russia against European countries.

The Baltic Sea hosts just under 20 underwater cables and pipelines. Some are communication lines, while others support Europe’s integrated energy network. Each is a convenient target.

The average depth of the Baltic Sea is about 55 meters, and most cables are laid at depths of no more than 80 meters. This makes them easy targets for simple sabotage, such as dragging an anchor along the seabed.

Energy infrastructure is also an obvious target. Russia began energy blackmail against Europe almost immediately after launching its full-scale invasion of Ukraine in February 2022, causing energy prices to surge and supplies to dwindle under fabricated pretexts.

As Europe strives to achieve independence from Russian resources, hybrid warfare has escalated to disrupt this independence. Damage incidents have increased during a critical period: on February 8, 2024, Lithuania, Latvia, and Estonia disconnected the last six high-voltage lines linking their energy networks to Russia and Belarus, synchronizing with the European energy system ENTSO-E. Ukraine’s Foreign Intelligence Service has warned that Russia may accompany this process with diversions, which we are already witnessing.

The Baltic Sea: A theater of unofficial conflict

Since 2022, the Baltic Sea has become a hotspot for undeclared hostilities between Russia and the European Union. Previously, reports highlighted spoofing—radio frequency interference disrupting maritime and civil aviation navigation. The epicenter of these disruptions is Kaliningrad, as detailed in earlier reports. Additionally, the Russian Baltic Fleet has displayed unprecedented activity: warships fire warning shots, and aviation engages in dangerous maneuvers. European officials claim such actions were unheard of before.

The new target is underwater infrastructure. Shadow fleets and old vessels, posing ecological risks, have also become weapons that directly threaten the energy security of Baltic Sea countries. To protect submarine cables and pipelines, NATO has launched a new mission to patrol the Baltic Sea. However, as stated by Nico Lange, former chief of staff at the German Ministry of Defense “We can’t really defend the entire critical structure—cables, pipelines, energy facilities, data centers—from hybrid attacks. Only now we understand how very, very vulnerable we are.”