If Russia continues showing formal behavior in relations with Ukraine in the gas issues Kyiv reserves the right to answer in kind, Ukrainian Deputy Prime Minister Yuriy Boiko said.

"If we take only partnership relations with Russian colleagues, we’ve always secured them in the peak periods, when it was important to maintain gas transit to Europe. Gazprom fulfilled its contract liabilities thanks to our support," Boiko said on Saturday in Kyiv region, answering questions of journalists.

"If Russian colleagues continue having such a formal approach, we reserve the right to use the contract only to buy [gas] and the full responsibility of gas transit to Europe by Russia's Gazprom will be laid only on them. We won’t lend our shoulder to them if they continue showing formal behavior, and we'll the same formal approach," he said.