National joint-stock company Naftogaz Ukrainy considers the refusal of Russia's Gazprom to supply natural gas under the advance payment made by Ukraine as violation of the contract and neglecting the award of the Arbitration Institute of the Stockholm Chamber of Commerce, the press service of Naftogaz has reported.

"We are surprised by the position of Gazprom. The company billed the contract as amended by the Tribunal. The bill was paid. We regard Gazprom's refusal to supply [gas] as a breach of the contract and failure to comply with the arbitration award. We are buying gas because we are executing the arbitration award," Naftogaz CEO Andriy Kobolev said.

According to him, not supplying prepaid gas, Gazprom is hindering the fulfillment of Naftogaz's obligations to purchase the minimum contract volumes.

"For four years of buying gas from European suppliers, we did not have any situation when we had to worry about whether we would get gas for which we paid," he said.

"Today's statement by Gazprom is another reason for European counterparts to consider whether to rely on the contractor who can bill you, get money and refuse to supply gas, and whether it is worth allowing this contractor to strengthen its already strong positions in their market thanks to the construction of the North Stream 2," Kobolev said.