If someone wants, can also cut the undersea cables. The attack to north stream proved that its possible, but this will cut out also himself from the connection.

Anyway, Italian internet providers association has already warned about this issue:

“Energy gratations, AIIP sounds the alarm: avert the risk of black-out of the Italian TLC network” https://www.aiip.it/razionamenti-energia-aiip-lancia-lallarm...