An undersea cable connecting Sweden and Estonia was damaged at about the same time as a pipeline and cable connecting Finland and Estonia, government officials have said.
Finnish investigators have identified a Russian-flagged ship and a Chinese-owned vessel operating in the area where the damage to the pipeline and cable occurred on October 8.
The Russian authority responsible for nuclear-powered vessels, Atomflot, denied that one of its ships had been involved.
Sweden’s Civil Defence Minister Carl-Oskar Bohlin said: “What we can say is that this damage has happened at a similar time and in physical proximity … to the damage that was previously reported to a gas pipeline between Estonia and Finland and a telecoms cable between Estonia and Finland.”
Swedish network provider Arelion confirmed one of its subsea fibre cables had been “partially damaged”.
“We currently do not know what caused the damage. The cable will be repaired over the next few weeks depending on the weather,” an Arelion representative said.
Estonian Economic Affairs and Communications Ministry said the damage occurred on a cable to Sweden about 50km west of Hiiumaa Island.
Rear Admiral Ewa Skoog Haslum, head of the Swedish navy said: “The situation at sea is very intense.
“There is a lot of traffic on the surface and everything that happens under the surface is 'deniable.' The challenge for us is to monitor this volume of water.”
European nations and Nato have become increasingly concerned about the vulnerability of critical infrastructure around and under the Baltic Sea.
The latest incidents follow explosions in September 2022 that ruptured the Nord Stream pipelines and cut Europe's supply of Russian gas.
Finland said on October 8 that the Baltic connector subsea gas pipeline and a telecoms cable connecting Finland and Estonia had been damaged in what may have been a deliberate act.
In an update, Finland's National Bureau of Investigation said it had used open sources to determine the vessels operating in the area at the time of the incident.
“Investigative measures have been focused on several vessels, including the NewNew Polar Bear and Sevmorput, but also on others which, according to data, had been in the area at the time of the damage,” the NBI said.
“Besides the movements of the vessels, their background and earlier activity are examined in co-operation with authorities from other countries,” it said.
The NewNew Polar Bear is a container vessel owned and operated by Chinese company NewNew Shipping, while Sevmorput is a Russian-flagged, nuclear-powered, cargo ship.
Sevmorput owner Atomflot, a subsidiary of Russian nuclear industry company Rosatom, rejected the claims as “groundless”.
Atomflot said that on the day at issue, the Sevmorput had been operating from Murmansk to St Petersburg and had passed through the Gulf of Finland “without slowing down”.
“The crew did not observe or record anything unusual, suspicious, or otherwise reportable,” Atomflot said.
NewNew Shipping declined to comment.