Kyiv is concerned by the pace of decline in Russian gas transit through Ukraine, Deputy Prime Minister Yuriy Boiko said at a briefing on Thursday.

"We have a contract on Russian gas transit and we are carrying it out in full. Moreover, we are not satisfied, since the volumes of transit through our country are falling and this is a topic for additional negotiations with our Russian colleagues," he said.

The measures Russia is taking "to bypass our country, we regard as an infringement of our natural interests and we oppose it," Boiko said. If Russia maintains it formal approach concerning gas imports, Ukraine will resort to the same posture on gas transit, he said.

"We have no contract providing for additional volumes of gas or Naftogaz Ukrainy's participation in ensuring contract implementation for gas deliveries between Gazprom and European companies in peak periods," he said.

Russian gas transit through Ukraine declined 0.4% year-on-year to 62.515 billion cubic meters in the first nine months of 2013, including 8.072 billion cubic meters in September, 22.5% more.

Gas transit through Ukraine totaled 84.261 billion cubic meters in 2012, 19.1% less than in the same period last year.