Lithuania said Wednesday that it would bring forward increased security of a key electricity cable linking it to neighbouring Poland, citing the potential for sabotage.
The EU and NATO member, along with its Baltic neighbours Latvia and Estonia, is set to decouple from the Russian power grid next month, the culmination of decades-long efforts to reduce reliance on Moscow.
The government said the Public Security Service agency would begin protecting key facilities of the Lithuania-Poland energy connection, known as LitPol Link, starting January 15, instead of in April as previously planned.
"All possible scenarios of sabotage or diversion are being assessed, from cybersecurity to certain physical actions," Prime Minister Gintautas Paluckas told reporters after a government meeting.
Lithuania also maintains an electricity grid connection with Sweden via the Baltic Sea, which will come under Public Security Service protection in April as scheduled.
On December 25, electricity and telecom Baltic Sea cables linking Estonia and Finland were damaged after suspected sabotage.
Finnish authorities said Wednesday that a tanker allegedly belonging to Russia's "shadow fleet" for evading Western sanctions, suspected of damaging the cables, was barred from sailing after Finnish inspectors found the vessel was unseaworthy.
The Eagle S, sailing under the Cook Islands flag, had already been seized by Finnish authorities as part of its criminal investigation into the suspected sabotage.
The three Baltic states will disconnect from the Russian grid on February 8 and join the European grid a day later.
Though they declared independence from the Soviet Union in 1991, their power grids have remained connected with Russia and Belarus and supply is managed from Moscow, meaning they still depend on Russia to ensure a stable electricity flow.
The countries decided to synchronise their power grids with the Continental European system in 2018, having secured funding from the European Union.
The Baltic states stopped buying Russian gas and electricity after Moscow invaded Ukraine in 2022.