Hazel Tyldesley, Sky News Online
Russia has cut back its gas supply to Belarus over unpaid debts, raising fears of disruption to European supplies.
Gas pipeline moument in Belarus
An old section of gas pipeline in Belarus: the nation transports Russian supplies
The head of Russian oil giant Gazprom said Belarus had failed to come up with the money and instead was offering equipment and machinery to cover a ?130m overdue payment.
But in a mocking attack, Russian President Dmitry Medvedev said only hard cash would settle the debt and ordered Gazprom to close the tap on Russian gas supplies to Belarus.
"Gazprom cannot accept anything towards the payment of the debt, neither pies nor butter not cheese nor pancakes nor other means of payment," Mr Medvedev said.
Following his remarks, Gazprom announced it was limiting its supplies of Russian gas to Belarus by 15% of daily volume.
It warned the gas cuts would be increased to 85% in the coming five days if the debt row was not resolved.
Russia's President Medvedev meets with Gazprom Chairman Miller
Russia's President Dmitry Medvedev meets with Gazprom chairman Alexei Miller
Belarus, which carries around a fifth of Russia's western-bound gas exports, reassured Europe that the flow of Russian gas to Europe via Belrus was not immediately interrupted after the move.
But analysts have nevertheless warned of a new 'gas war' - following last year's spat between Russia and Ukraine which left many Europeans with major fuel shortages during a cold snap in January.
Relations between Moscow and Minsk have worsened as the Belarussian President Alexander Lukashenko seeks closer ties with the European Union.
Mr Lukashenko has refused to agree on recent customs rules and has argued that Belarus should be paying less for oil and gas if Russia is serious about economic cooperation.
Russia supplies a quarter of Europe's gas needs and uses Belarus, which borders EU member Poland, as one of two key transit routes or oil and gas to the continent.
Gazprom has said it has the capacity to reroute the European gas supplies away from Belarus, and that the impact of the cuts would be less severe due to lower summer-time needs.