Nearly three and a half decades after leaving the Soviet Union, the Baltic countries of Estonia, Latvia and Lithuania will no longer be connected to the electricity grids of Russia and Belarus starting this weekend, as they turn entirely to their European Union allies.

Cutting off electricity links with oil- and gas-rich Russia has both geopolitical and symbolic significance. Work on this has accelerated since Russian President Vladimir Putin ordered an attack on Ukraine three years ago, which has strained Moscow's relations with the EU.

Lithuanian President Gitanas Nauseda recently said that it was about "physical separation from the last remaining element of reliance on the Russian and Belarusian energy systems."

European Commission President Ursula von der Leyen and other dignitaries are expected at a ceremony in central Vilnius on Sunday when a specially built nine-meter-high clock will count down the final seconds of the Baltic countries' electricity connection to Russia.

In recent years, 16 power lines connecting the Baltic states with Russia and Belarus have been dismantled as a new network connecting the three countries to the rest of the EU was created, including undersea cables in the Baltic Sea.