The flow of electricity between the Baltic countries of Estonia, Latvia and Lithuania and Russia was officially severed Saturday morning after officials switched off the Soviet-era grid’s transmission lines and prepared to join the rest of Europe on Sunday.

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.

The so-called Brell power grid - which stands for Belarus, Russia, Estonia, Latvia, Lithuania - is controlled almost entirely by Moscow and has long been seen as a vulnerability for the former Soviet republics, which are now Nato members.