Russia has been closing down gas deliveries to Belarus over what it claims is a nearly $200-million (U.S.) debt for earlier supplies. Until Wednesday, the cut-off was expected to not affect any countries that receive their supplies through Belarus.

Lithuania, which gets all of its Russian gas supplies via Belarus, has now become the first EU customer affected by the dispute.

Belarus’ Energy Ministry has warned in a letter to the European Commission on Monday that Russian cuts of more than 15 per cent could lead to transit shortages.

Russia's state-controlled natural gas monopoly Gazprom initially reduced supplies to Belarus by 15 per cent on Monday, then decreased them by another 15 per cent the following day and deepened them to 60 per cent Wednesday. It warned Belarus it would eventually cut the deliveries by 85 per cent if it refuses to pay off its debt.

Gazprom has insisted that European customers will not be affected by the shut-off as the company can reroute gas supplies through another transit pipeline crossing Ukraine.

Lithuania’s energy company Lietuvos Dujos said Belarus cut the supplies Wednesday without warning. Lietuvos Dujos says Latvia has assured its Baltic neighbour that it will be able to supply Lithuania with sufficient gas to meet its needs.

Other EU customers receiving Russian gas via Belarus – Poland and Germany – haven’t yet reported any drop in supplies.

The European Union spokeswoman Marlene Holzner said the EU’s energy commissioner, Guenther Oettinger, told Russian and Belarus officials in Tuesday telephone calls that “Europe must not be taken hostage in this dispute” and expects that gas flows will remain uninterrupted.

About 80 per cent of Russian gas exported to Europe normally goes through Ukraine, while the rest is carried via Belarusian pipelines.

Russia has cut gas supplies to both Ukraine and Belarus several times in recent years due to payment disputes, and many European consumers have suffered amid freezing winter temperatures. The cutoffs has prompted the EU to search for alternate gas supply routes.

Russia is Belarus’ main ally and sponsor, but relations between the two former Soviet countries have been strained by financial arguments. Belarus has insisted that Russia should provide cheaper oil and gas as part of the customs union deal that is to come into force next month, but Russia has refused.

Belarus has refused to pay a higher gas price this year and insisted that Russia owes it $260-million in transit fees.

Gazprom said in a statement Wednesday that Belarus had paid for May deliveries at a higher price thus “recognizing the need” to pay the prices that Gazprom insisted on. But Belarus' $192-million debt for the supplies delivered during the first four months of the year is still pending, the company said.