At least 11 cables running along the Baltic seabed have been damaged since October 2023, officials say.
The latest of these incidents occurred last weekend, a fibre-optic cable linking Latvia and the Swedish island of Gotland was damaged.
While operators note that damage to submarine cables is relatively common, the frequency and concentration of incidents in the Baltic Sea has led to suspicions of deliberate damage.
One of the first incidents that drew public attention occurred last November, one of the three Baltic Sea communication cables from the Swedish island of Gotland to Lithuania was damaged.
Swedish media also reported earlier this month on attempts to damage the NordBalt submarine power cable linking Lithuania and Sweden.
Politicians have pinned the incidents on a Russian-organised hybrid warfare.
What’s is there on the Baltic seabed?
Various electricity and communication cables and gas pipelines connect the nine countries that border the Baltic Sea.
These include the 152 km Balticconnector gas pipeline, which carries gas between Finland and Estonia, a high-voltage cable linking the electricity grids of Sweden and Germany, and the 1,173 km C-Lion1 telecommunications cable between Finland and Germany.
“In the last two months alone, we have seen damage to a cable connecting Lithuania and Sweden, another connecting Germany and Finland, and most recently, a number of cables linking Estonia and Finland. Investigations of all of these cases are still ongoing. But there is reason for grave concern,” NATO Secretary General Mark Rutte said in mid-January.
While did not name Russia as the agent behind all the incidents, he suggested they were part of “hybrid warfare”.
Meanwhile, Lithuanian President Gitanas Nausėda has commented that although there is no evidence yet to unequivocally attribute the incidents to Russia, “the coincidence of the timing of the incidents, that we have had so many incidents in the past year and that they are increasing, raises reasonable doubts”.
He also hopes that the actions of NATO, the Nordic countries in the Baltic Sea will deter attempts to damage underwater infrastructure.
“We will do everything in our power to make sure that we fight back, that we are able to see what is happening and then take the next steps to make sure that it doesn’t happen again. And our adversaries should know this,” Rutte said earlier this month when he announced a new NATO mission, Baltic Sentry, to protect the Baltic Sea underwater infrastructure.
The alliance is deploying warships, maritime patrol aircraft, and maritime drones to provide enhanced surveillance and deterrence.
Sabotage or accidents
A recent report by the Washington Post has quoted unnamed officials from three countries involved in ongoing investigations, suggesting that “ruptures of undersea cables that have rattled European security officials in recent months were likely the result of maritime accidents rather than Russian sabotage”.
The publication called this “an emerging consensus among US and European security services”.
Several Western intelligence officials, speaking on condition of anonymity, also told the AP news agency that the recent incidents of damage to cables were likely accidents, apparently caused by anchors dragged by poorly maintained and undermanned vessels.
A senior intelligence official told the AP that ship logs and mechanical failures of ships’ anchors are among a number of indications that this is not Russian sabotage. Moreover, Russian cables were also cut.
Operators urge vigilance
The European Submarine Cable Association, which represents cable owners and operators, noted in November, following reports of failures at two Baltic Sea links, that on average a submarine cable is damaged somewhere in the world every three days.
In northern European waters, the main causes of damage are commercial fishing or ship anchors, she said.
On Sunday, a Maltese-flagged vessel, the Vezhen, was detained by Swedish authorities on its way to South America with a cargo of fertiliser after breaching a fibre-optic cable linking Latvia and Sweden.
The Bulgarian company Navibulgar, which owns the vessel, claimed that the damage was unintentional and that the crew of the vessel, while navigating in extremely poor weather conditions, noticed that its left anchor appeared to be dragging on the seabed.
Meanwhile, Finnish police suspect that the oil tanker Eagle S, which on December 25 damaged the Estlink 2 power cable and two other communication cables connecting Finland and Estonia, is part of a Moscow “shadow fleet” used to evade sanctions on Russian oil exports.
The Finnish authorities intercepted the tanker shortly after it left a Russian port and apparently broke the cables while at anchor. Finnish investigators say the ship left an anchor trail of almost 100 km on the seabed.
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