An undersea fiber optic cable between Latvia and Sweden was damaged on Sunday, likely as a result of external influence, Latvia said, triggering an investigation by local and NATO maritime forces in the Baltic Sea.

A subsea cable connecting Latvia to Sweden’s Gotland island is the latest cable to be damaged in the Baltic Sea. Owned by Latvia’s State Radio and Television Centre (LVRTC), the cable’s Ventspils–Gotland segment was damaged early on January 26, at depths of 100m.

After a fiber optic cable was damaged near Sweden, Latvia sent a patrol boat to inspect a suspicious vessel in the Baltic Sea. Sweden later said it seized a vessel believed to have carried out the sabotage.