Reports from Nordic countries reveal concerns about Russian fishing vessels appearing in unusual places close to military bases and firing ranges, raising questions about the presence of Russian spy ships in Nordic waters. The Russian fishing vessel Taurus, which delivered fish to Norway between 2015 and 2022, has been spotted near military bases where all naval traffic is prohibited, and on one occasion, it passed by a major NATO exercise. The Norwegian Intelligence Service has reported that more than 50 Russian spy ships could be in Nordic waters.

Russia has denied the accusations, calling them "baseless." The Dutch intelligence officials also warned that Russia had tried to gain intelligence to prepare for the potential sabotage of critical infrastructure in their patch of the North Sea.

The investigation comes after Finland became the 31st member of NATO, doubling the US-led alliance's border with Russia. Moscow warned that further NATO expansion would not bring more stability to Europe and said it would scale up forces near Finland if the alliance sent any troops or equipment to the new member country.