The EU receives around one-quarter of its gas from Russia.
Russia's state-controlled gas monopoly Gazprom has threatened to cut supplies to Belarus if Minsk fails to accept a steep increase in prices from January 1.
Belarus has said that if Russia cuts its supplies, it will disrupt deliveries to Western Europe. Around 20 percent of Russia's gas to Europe is shipped via Belarus.
In Moscow today, Gazprom spokesman Sergei Kupriyanov warned Minsk not to disrupt flows through the Yamal-Europe pipeline, which runs through Belarus.
"The Yamal-Europe gas pipeline is a pipeline intended exclusively for exports [to Europe]," Kupriyanov said. "Of course, it has technological joints with Beltranshaz networks, but they are locked and sealed, and any unsanctioned change in the conditions of use of these joints will be immediately detected here at the central control department."
"Gazprom will do everything that has to be done to ensure a reliable and full supply of gas to our European customers through Belarusian territory," Kupriyanov added. "We will find a way to deliver our gas through our pipeline without any obstacles."
Ukraine's Fuel and Energy Minister Yuriy Boyko said Kyiv can help European customers by increasing transit of Russian gas through its territory if the dispute between Moscow and Mink disrupts supplies.
The main Moscow-Minsk railway line(Tass)
TO MERGE OR NOT TO MERGE: For over a decade, Moscow and Minsk have been working on a project to form a single state, the Russia-Belarus Union. However, every time the two countries seem on the verge of making progress, one or the other steps back, leaving the entire effort in doubt.