Belarus has threatened to cut supplies of Russian-produced electricity that transits its territory en route to the Russian enclave of Kaliningrad.

Belarus has claimed that Russia is supplying Kaliningrad, despite the lack of a new agreement on transit fees between the two countries.

"This compels the Belarusian side to think of cutting the unauthorised commercial transit of electricity," the Belarus state power company has announced in a statement on Monday.

Meantime, the dispute between both countries over Russian oil supplies to Belarus has remained unresolved. There were media reports that supplies had been stopped on Monday, but these have been denied as untrue by both sides.

"We are continuing uninterrupted transit to Western European customers," said Russian Deputy Prime Minister Igor Sechin, as quoted by Interfax news agency.

"The information is false, oil is still being supplied to Belarus both for transit and for processing," a Belneftekhim spokeswoman told the Ria Novosti news agency.

The two former Soviet republics have failed to sign a new agreement on Russian oil deliveries for 2010, which was supposed to be signed by the end of 2009.

Russian Prime Minister Vladimir Putin stated he hoped a deal with Belarus would soon be completed.

The dispute centers on the preferential tariff that Belarus has been paying since 2007 for Russian oil. It has been selling on Russian crude or refined oil at world prices.

Russia has insisted that Belarus should pay excise tax on oil imports. Belarus maintains that this would contradict an agreement made last autumn.

Moscow has assured on Sunday that talks to resolve the matter were ongoing. "The negotiation process is not finished. Negotiations will continue," a spokeswoman for the Russian Energy Ministry had said.

Early in 2009, Russia cut off supplies to Ukraine in a row that left much of Eastern Europe and the Balkans short of gas at the height of winter. Bulgaria, with an almost total dependence on Russian energy supplies, was particularly hard-hit.