Russia and Ukraine were still arguing over gas supplies again on Wednesday.
Russia began pumping gas meant for Europe via Ukraine on Tuesday, but the EU says little or none is flowing yet to countries with urgent shortages.
European Commission chief Jose Manuel Barroso called the crisis "unacceptable and incredible".
Russia accuses Ukraine of deliberately cutting gas to Europe, but Kiev says Russia has provided so little gas there is not enough pressure in the pipelines to pump it on.
Gazprom is claiming $US614 million from Ukraine in unpaid gas bills and wants $US450 per 1,000 cubic metres of gas in 2009. That is similar to rates paid by EU customers. Last year's price was $US179.5 per 1,000 cubic metres of gas.