Interfax-Ukraine news agency quoted Naftogaz's executive, Andrei Kobolev, as saying that the company had paid for gas supplies from Russia for the month of March.
But a spokesman for Russian energy giant Gazprom said that the payment was only enough for one additional day of delivery if gas continues to be pumped to Ukraine at the current rate.
Following a bruising dispute over prices and debt that raised fears of supply disruptions in Europe, Russia and Ukraine signed a deal in October requiring Kiev to pay in advance for gas shipments. President Vladimir Putin and other government officials warned earlier this week that Russia would cut off supplies to Ukraine by the end of the month barring further pre-payments.