The three Baltic states disconnected their electricity systems from Russia's power grid on Saturday, the region's operators said, part of a plan designed to integrate the countries more closely with the European Union and boost security.

Lithuania took a significant step by disconnecting its electricity system from Russia’s power grid. This is part of a broader plan that the three Baltic states—Lithuania, Latvia, and Estonia—have been working on for years.

Three Baltic states have cut ties with Russia’s power grid to join the European Union’s network in “a victory for freedom...