Russia has said the decision to stop pumping oil through a key pipeline to Europe was forced upon it by events outside of its control.
Transneft's decision has disrupted oil supplies to central Europe
The comments came as officials from Belarus and Russia began talks aimed at resolving an escalating energy dispute.
Russia has been condemned by the European Union for cutting off its oil supplies without consultation.
German chancellor Angela Merkel dubbed the move "unacceptable" and one that "destroyed trust" in Russia.
Ms Merkel also said the current conflict illustrated that Europe's energy sources should be more diverse.
European Commission President Jose Manuel Barroso had said earlier that energy companies should not be allowed to cut off oil supplies unannounced.
However, Russian Energy Minister Viktor Khristenko said the row with Belarus which led to the pipeline closure constituted a "force majeure" - which means that the events are beyond the country's control and it is free of its obligations.
Russia has accused Minsk of stealing oil and on Monday stopped oil exports to Belarus, a move that, effectively, also halted exports to Germany, Poland and beyond.
The European Commission is convening its oil supply group on Thursday to discuss the impact of the shut-off, amid reports that some refiners are now being affected.
Meanwhile, Russian president Vladimir Putin has told his government to do everything in its power to protect the interests of its oil customers.
However, he has also warned that the country may have to cut oil output, which some experts suggest to be a sign that he is hoping to force Belarus into a climb down.
"It's necessary to secure the interests of Russian companies that have obviously encountered losses," Mr Putin added.
Despite the pipeline closure, European markets should be able to cope with the drop in exports, the International Energy Agency (IEA), a multilateral energy think-tank said.
European legislation requires member states to hold emergency stocks, which the European Commission said stood at more than 120 days.
The IEA added that even if the shut-off was a prolonged one, refineries "could source crude supplies from alternative routes, and some of them are already organising alternative supplies".
Azerbaijan is also in dispute with Russia and has suspended oil exports to Russia following a pricing dispute with state-backed gas giant Gazprom.
Russia has been pushing prices higher and started to charge duties on its crude oil shipments.
Russia's moves prompted Belarus to impose a transit tax on the Russian oil being shipped through pipelines that crossed its territories.
Belarus then launched a legal action against Transneft when the Russian oil pipeline monopoly refused to pay the charges.
Belarus has said it is ready to negotiate over its decision to introduce a $45 (£23) per tonne charge for oil shipped through its territory.
The latest energy wrangle comes almost a year after deliveries of Russian natural gas to much of Western Europe were disrupted during a dispute over pricing between Russia and Ukraine.