Nearly 3 1/2 decades after leaving the Soviet Union, the Baltic countries of Estonia, Latvia and Lithuania this weekend will flip a switch to end electricity-grid connections to neighboring Russia and Belarus — and turn to their European Union allies.

Lithuania has warned of potential risks linked to the change, including possible cyber attacks, which will happen Saturday morning.

Lithuania, Latvia and Estonia will disconnect from the Russian power grid on Saturday, severing Soviet-era energy ties with their neighbor to the east. A countdown clock in Lithuania's capital, Vilnius,