Baltic undersea infrastructure is in news again — who's behind past damage?

Two back-to-back alleged sabotage of undersea internet cables in the Baltic Sea have once again highlighted the vulnerability of such infrastructure and raised the question about who could be behind the 'attacks'.

On Sunday, a communications cable between Lithuania and Sweden was cut. A day later, another subsea cable between Finland and Germany was severed, 95 to 105 kilometres from the first.

German Defence Minister Boris Pistorius described the incident as "a wake-up call for European resilience" and urged collective action to safeguard critical infrastructure. He pointed fingers at Russia.

"Russia poses not just a military but also a hybrid threat, and Europe must adopt a broad approach to defence," he said speaking in Brussels.

"No one believes these cables were severed by mistake, and I also don't want to believe versions that it was anchors that by chance caused damage."

The Danish military says it is monitoring a Chinese vessel Yi Peng 3, which has been spotted in the vicinity of the cables.

The cables were damaged near Sweden's Oland Island, a key location for maritime activity in the Baltic.

Sweden's Minister for Civil Defence, Carl-Oskar Bohlin, emphasised the urgency of determining the cause, telling SVT News: "It is absolutely central that we clarify why two cables in the Baltic Sea have been simultaneously damaged."

The Baltic Sea, bordered by NATO members and Russia, has had a troubled history of infrastructure-related incidents, with several high-profile disruptions seen over the past decade.

Here is a list of past damages and who was responsible for them:

Cable damage near Finland and Estonia: In October 2023, undersea telecom cables near Finland and Estonia were damaged by what investigators concluded was a Chinese container ship dragging its anchor. Although the exact intent behind the incident remains unclear, Finnish authorities have not ruled out negligence or intentional interference.

Nord Stream explosions: The Nord Stream 1 and 2 gas pipelines were blown up in September 2022. It remains one of the most infamous cases of infrastructure sabotage. European states, experts, and media were quick to blame Russia for damaging the pipelines, which played a crucial role in supplying gas to EU consumers. Subsequent German investigations found that Ukrainians were behind the attack on Nord Stream pipelines.

Yamal-Europe pipeline leak: A leak in the Yamal-Europe pipeline disrupted gas flows through Poland in 2021, with initial suspicions focused on Russian involvement. However, investigations revealed that construction flaws and third-party interference during installation were to blame.

The Baltic Sea hosts a dense network of undersea cables and pipelines vital for Europe's energy and communication needs.

Its proximity to Russia and its role as a critical route for NATO make it a potential hotspot for sabotage, with analysts at the European Policy Centre highlighting that that "even minor disruptions can have outsized economic and strategic consequences".

The latest damage has led to renewed European calls for comprehensive monitoring and protection of underwater assets, with Germany and Finland emphasising the importance of shared infrastructure security and pledging to increase surveillance.

"This is not just about the Baltic Sea; it's about protecting Europe's connectivity," said Finnish Prime Minister Petteri Orpo at a recent press conference.

As investigations into the Baltic cable cuts continue, experts caution against premature conclusions. Past cases, such as the Nord Stream and Finland-Estonia incidents, have demonstrated how initial suspicions can shift as evidence emerges.