Estonia, Latvia and Lithuania - all former Soviet republics that are now part of the European Union and NATO - wanted to block Russia's ability to blackmail them geopolitically through the electricity system.

"We have eliminated any theoretical possibility of Russia using control of the energy system as a weapon," Lithuanian Energy Minister Zygimantas Vaichunas told AFP on Saturday.

European Energy Commissioner Dan Jorgensen said, "This is indeed a historic day."

 "I like the light more when there are no Russian electrons," he told reporters in the Estonian capital Tallinn.

"It is important to stress that this is about security... No European country should be dependent on Russia for anything," he added.

Vaičunas said the Baltic states had completed the disconnection process at 9:09 a.m.

Later, Latvia physically cut the power line to Russia.

"Now we have full control over our power grid," Latvian Energy Minister Kaspars Melnis told reporters while holding a piece of the dismantled wire.

Vaičunas said the Baltic states were now operating in what he called "isolated mode" before integrating with the European grid on Sunday.

A total of 1.6 billion euros ($1.7 billion) - mostly EU funds - have been invested in the synchronisation project in the Baltic states and Poland.

European Commission President Ursula von der Leyen was due to attend a ceremony with Baltic leaders in Vilnius on Sunday.

The Baltic states have long been preparing to integrate with the European grid but have faced technological and financial problems.

The transition became more urgent after Russia invaded Ukraine in 2022, with the Baltic states worried about becoming the next target.

They stopped buying Russian gas and electricity after the invasion, but their power grids remained connected to Moscow-controlled Russia and Belarus.

This has left them dependent on Moscow for a steady flow of electricity, which is critical for factories and facilities requiring reliable power.

Several undersea telecommunications and power cables have been severed in the Baltic Sea in recent months.

Some experts and politicians have accused Russia of waging a hybrid war, a claim Moscow denies.

Authorities were on alert Saturday for potential sabotage or other risks associated with the network switchover.

Latvian network operator ACT said no outages had been recorded so far, indicating no provocation from Russia.

"They cut the power to the same line on their side as well, and the biggest surprise today is that there are no surprises," ACT CEO Rolands Irklis told AFP.

Lithuania's state grid operator Litgrid also said Russia had fully cooperated during the outage process.

Litgrid head Rokas Massiulis pointed out that "when you are part of the same (electricity) system, you cannot harm the other without harming yourself."

Massioulis said Russia must ensure the energy security of the Russian exclave of Kaliningrad, "which partly depends on us."

Due to the separation of the Baltic states, the energy system in Kaliningrad will no longer have a connection to the grid of mainland Russia.

The exclave is located between Lithuania and Poland and has no border with the rest of Russia.

Kaliningrad has been building up its power generation capacity for years and Kremlin spokesman Dmitry Peskov dismissed any concerns.

Asked about the shutdown last week, he said, "We have taken all measures to ensure the continued reliable operation of our unified energy system."

The Baltic states will operate in "isolated mode" for about 24 hours to test their frequency or power levels, according to Litgrid.

"We need to carry out some tests to assure Europe that we are a stable power system," Massiulis said.

"We will be turning power plants on and off, watching how the frequency fluctuates and assessing our ability to control it."

The countries will then integrate into the European power grid through Poland.

Poland's power grid operator PSE said it would use helicopters and drones to patrol the link with Lithuania.

In Estonia, police and the volunteer defence corps will man critical electricity infrastructure until next weekend due to the alleged risk of sabotage.

Lithuania was also guarding the infrastructure. This week its armed forces began exercises in a region bordering Poland to secure the power link. I BGNES