Vilnius, Lithuania. 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.

This came more than three decades after the collapse of the Soviet Union, ending the Baltics' final ties to oil- and gas-rich Russia. For the three countries, as well as the rest of Europe, the move was steeped in geopolitical and symbolic significance.

“The Baltic energy system is finally in our hands, we are in full control,” Lithuania Energy Minister Žygimantas Vaičiūnas told reporters.

On Saturday, all remaining transmission lines between them and Russia, Belarus, and the Russian exclave of Kaliningrad, wedged between EU members Poland and Lithuania and the sea, were switched off one by one. Lithuania first -- where a specially-made 9-meter (about 29-foot) tall clock in downtown Vilnius counted down the final seconds -- then Latvia a few minutes later, followed by Estonia.

For 24 hours after detaching from the Soviet-era grid, the Baltic Power System will operate independently. If all goes as planned, the power system will merge with the European energy networks on Sunday afternoon through several links with Finland, Sweden and Poland.

European Commission President Ursula von der Leyen, as well as the presidents of Poland and the Baltic states, are expected for a ceremony in Vilnius on Sunday evening along with other dignitaries.

The Baltic countries, which are all NATO members, have often had chilly ties with Russia since declaring independence from the USSR in 1990 -- and relations soured further over Russia’s full-scale invasion of Ukraine in 2022.

Sixteen power lines that used to connect the Baltic states with Russia and Belarus were dismantled over in recent years as a new grid linking them with the rest of the EU was created, including underwater cables in the Baltic Sea.

“This is physical disconnection from the last remaining element of our reliance on the Russian and Belarusian energy system,” Lithuanian President Gitanas Nausėda told The Associated Press in a recent interview.

The three Baltic countries, which together have a 1,633-kilometer-long (1,015-mile) border with Russia and Belarus, informed Moscow and Minsk of the disconnection plan in 2024 to head off any hostile reaction.

“We have a protocol with the Russians on how everything should be disconnected,” Rokas Masiulis, CEO of Litgrid, told reporters on Saturday.

Leaders of all three countries assured their nations that the shift would go smoothly but special measures were taken to prevent possible provocations.

In Latvia, the National Armed Forces and the National Guard were instructed to carry on their duties in a reinforced mode. No incidents were reported early Saturday.

The Kaliningrad region, which has no land ties to mainland Russia, already relies on its own power generation, according to Litgrid.