Two countries, Sweden and Finland, that recently joined NATO experienced severed undersea communication cables within a day of one another. There are strong suspicions that this was an act of sabotage.

A communications cable between Lithuania and Sweden was cut on Sunday morning around 10:00 a.m. local time, a spokesperson from telecommunications company Telia Lithuania confirmed to CNN.

The company’s monitoring systems could tell there was a cut due to the traffic disruption, and that the cause was likely physical damage to the cable itself, Telia Lithuania spokesperson Audrius Stasiulaitis told CNN. “We can confirm that the internet traffic disruption was not caused by equipment failure but by physical damage to the fiber optic cable.”

Another cable linking Finland and Germany was also disrupted, according to Cinia, the state-controlled Finnish company that runs the link. The C-Lion cable – the only direct connection of its kind between Finland and Central Europe – spans nearly 1,200 kilometers (730 miles), alongside other key pieces of infrastructure, including gas pipelines and power cables.

The second cable was cut early Monday morning. CNN reports the places where the two cables were severed is only about 60-65 miles apart. No one is saying explicitly that this was sabotage yet because the damaged cables still haven't been examined by repair crews. However, they are willing to say that there's no way this happened without human intervention of some kind.

“At the moment, there is no way to assess the cause of the cable break, but such breaks without external impact do not happen in these waters,” said Ari-Jussi Knaapila, the chief executive of Cinia.

However, he cautioned that the damage could have been caused by a trawler or a ship that had put down an emergency anchor. The company pointed out that the fibre optic cables are sheathed in a double-armoured steel casing.

So consider that a caveat but its also worth noting that back in September the US warned there was an increasing risk of Russian sabotage of undersea infrastructure in the Baltic Sea.

The US has detected increased Russian military activity around key undersea cables, and believes Russia may now be more likely to carry out potential sabotage operations aimed at disabling a critical piece of the world’s communications infrastructure, two US officials told CNN.

Russia has put increasing emphasis on building up a dedicated military unit, which deploys a formidable fleet of surface ships, submarines and naval drones, according to one of the officials. The unit, the “General Staff Main Directorate for Deep Sea Research,” is known by its Russian acronym GUGI.

That warning followed a 2023 report on a network of Russian spy ships operating in the area to map potential sites for sabotage.

Russia has a fleet of suspected spy ships operating in Nordic waters as part of a program for the potential sabotage of underwater cables and wind farms in the region, according to a joint investigation by the public broadcasters of Sweden, Denmark, Norway and Finland.

The broadcasters used data analysis, intercepted radio communications and intelligence sources to show how around 50 boats had been gathering intelligence for the past 10 years, using underwater surveillance equipment to map key sites for potential sabotage, Norway’s NRK and Sweden’s SVT reported...

One ship at the center of the investigation, the Admiral Vladimirsky, is officially used for underwater research expeditions, but is, according to the report, a Russian spy ship. The broadcasters tracked the boat’s movements and found it had traveled for a month through Nordic waters with its transmitter turned off to remain hidden, sailing close to wind farms, as well as through naval training areas of the Swedish Armed Forces, SVT reported.

So, officially, we don't know who did this and it may be a while before the evidence is gathered and revealed, but unofficially I think everyone suspects this was Russia.