The companies that own the two cables both said it was not yet clear what had caused the outages.
“It’s not a partial damage, it’s full damage,” said a spokesperson for Arelion, owner and operator of the cable linking Lithuania and Sweden.
Cinia, owner of the cable linking Finland and Germany, said it was not possible to say what might have caused the breach until repairs had started.
The company has said repairs of this nature typically take five to 15 days.
Ruben Brekelmans, the Dutch defence minister, made clear he had no specific information about who was to blame, but said: “We see increasing activity of Russia, especially, on our seas, aimed at espionage and possibly even sabotage of our vital infrastructure.”