Investigations are underway after two undersea data cables connecting Finland to Germany and Sweden to Lithuania were severed on Monday. NATO member states have called the incidents potential sabotage and warned of increasing hybrid threats from Russia.

The C-Lion1 cable, which spans 750 miles between Helsinki, Finland, and Rostock, Germany, was found damaged southeast of the Swedish island of Öland in Sweden’s exclusive economic zone. Another cable linking Sweden and Lithuania was also cut, though details remain limited.

Finnish telecommunications company Cinia, which operates the C-Lion1, confirmed the damage, stating the break could not have occurred without external impact. No seismic activity was recorded in the region at the time.

Repairs are underway for the C-Lion1 cable, but Cinia estimates it could take 5 to 15 days to restore functionality.

German Defense Minister Boris Pistorius described the incidents as a “very clear sign that something is afoot,” emphasizing the improbability of accidental damage. Speaking in Brussels, Pistorius noted the absence of evidence but pointed to sabotage as the likely cause.

Finland and Germany issued a joint statement expressing concern over the damage to critical infrastructure, emphasizing that European security faces threats not only from Russia’s military actions in Ukraine but also from hybrid warfare tactics. Swedish authorities are investigating, as the damaged section of the C-Lion1 lies within their waters.

Polish Foreign Minister Radoslaw Sikorski also warned against continued sabotage, stating that such acts by Russia could lead to the closure of additional consulates in Poland.