"Today, history is made," EU chief Ursula von der Leyen told a ceremony in Lithuania's capital. "This is freedom, freedom from threats, freedom from blackmail."

Polish President Andrzej Duda, praised it as a "truly symbolic moment" that would make the region "more secure and resilient".

"It is the final step towards emancipation from the post-Soviet sphere of dependence," he added.

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 three Baltic states.

Now Nato members, they have not purchased electricity from Russia since 2022, but their connection to the Brell grid left them dependent on Moscow for energy flow.