Ukrainian state energy firm Naftogaz said on Monday Russia's Gazprom had violated the terms of a supply agreement by failing to supply gas that Kiev had paid for in advance.
Naftogaz said it had ordered 114 million cubic metres (mcm) of gas from Russia last Thursday, which had to be delivered on Sunday. Of this Gazprom supplied only 47 mcm, Naftogaz said.
(Reporting by Natalia Zinets; Writing by Alessandra Prentice)