Q+A - Russia's row with Ukraine over gas supplies

(Reuters) - A contract dispute between Russia and Ukraine has disrupted gas supplies to countries in the European Union, which gets about a fifth of its needs via pipelines through Ukraine.

WHY DID THE ROW START?

Russia and Ukraine failed to agree a new contract for gas supplies in 2009 before a New Year's Eve deadline set by Russian negotiators.

Russian gas export monopoly Gazprom said during the talks it wanted to raise the price it charged Kiev from $179.5 (123.55 pounds) to $250. Kiev said it did not want to pay that, and made any price rise conditional on Gazprom paying more for pumping gas to Europe across Ukrainian territory.

WHY IS THERE LESS GAS GOING TO EUROPEAN CONSUMERS?

Gazprom cut off all gas for Ukraine's domestic use on New Year's day. This is not as simple as it sounds: Ukraine's gas, goes through the same network of pipelines as the gas intended for customers in Europe.

So what Russia did was to reduce the total volumes it was pumping by the amount Ukraine imports. That meant a reduction from the usual 400 million cubic metres a day to about 300 mcm/day.

What happened next is under dispute. Russia accused Ukraine of stealing gas intended for Europe, and using it for its own needs. On Monday, it cut gas supplies going through Ukraine further, by about one sixth. It said this was equivalent to the amount Kiev was siphoning off. On Tuesday, Gazprom accused Kiev of unilaterally shutting down at least three major export pipelines.

Ukraine has a different account of events. It denied siphoning off gas, saying only it had used some gas intended for export to maintain pressure in the pipeline network.