The European Union has demanded an immediate resumption of Russian natural gas to EU countries after Russia cut off supplies to Ukraine.
The EU presidency said Friday that supply commitments must be honored under all circumstances.
European countries began to suffer from reduced gas supplies Friday after Russia cut deliveries to Ukraine on Thursday over a price dispute.
The EU Commission said Hungary suffered a drop of almost a quarter of its contracted supply of 10 million cubic meters.
Poland reported a six percent drop in gas deliveries but says Russia's state-run natural gas firm, Gazprom, made up the difference by increasing deliveries through Belarus.
And Romanian officials say they have experienced a 30 to 40 percent drop in Russian gas supplies.
The Czech Republic, which holds the rotating European Union presidency, scheduled a special meeting of envoys from all 27 EU states in Prague Monday to discuss the crisis.
Earlier, Russia suggested calling an emergency session of the European Parliament to air its grievances.
Ukraine's Foreign Ministry sent envoys to European capitals to discuss the crisis.
Russian authorities also accused the Ukrainians of gas theft, a charge Ukrainian officials denied.
Meanwhile, the chairman of the Russian gas monopoly, Gazprom, Alexei Miller, said his firm is now demanding that Ukraine pay a 2009 unit price of 418 dollars per one thousand cubic meters of gas.
Miller said the Ukrainian utility Naftohaz earlier rejected a price of $250.
Ukraine says the dispute centers on Gazprom's refusal to negotiate increased transit fees for Russian gas carried by pipeline through Ukraine to western European consumer-countries.
The U.S. State Department is urging both countries to resolve the dispute quickly and with transparency.