The Baltic Sea region is on alert and the NATO alliance has boosted its presence after a series of power cable, telecom and gas pipeline outages since Russia invaded Ukraine in 2022. Most were caused by civilian ships dragging their anchors.
Finnish telecom operator Cinia said on Friday it had detected minor damage on its C-Lion1 undersea fibre-optic link connecting Finland and Germany but that there was no impact on the cable's functionality.
Swedish police were investigating the matter because the breach had occurred in Sweden's economic zone, police spokesperson Mathias Rutegard told Reuters.
"The preliminary investigation relates to suspected sabotage," Rutegard said.
It is the third time in recent months that Cinia's C-Lion1 cable was damaged, after it was completely severed in November and December last year.
The Swedish coastguard said it had sent a vessel to help investigate the incident off the island of Gotland.
Sweden's prosecution authority said it was not involved in the investigation of the cable breach.
Prime Minister Ulf Kristersson said the government was being briefed and that damage to any undersea infrastructure was particularly concerning amid the current security situation.
Last month, NATO launched its new Baltic Sentry mission, after several cables under the Baltic Sea were damaged or severed in 2024.
Finnish police said late last year they were investigating whether a Russian ship was involved in the sabotage of an electricity cable running between Finland and Estonia.
