Ukrainian officials are pressing Moscow for a better deal for natural gas. The country pays around $400 per 1,000 cubic meters of gas from Russia.
Russia aims to allay energy security concerns through its Nord Stream gas pipeline through the Baltic Sea and the planned South Stream project for southern Europe.
Gazprom officials last month suggested construction on South Stream depended on the status of negotiations with Ukraine, which hosts most of Russia's gas bound for Europe.
Alexander Medvedev, head of exports for Gazprom, suggested the Russian gas monopoly was committed to South Stream regardless of the status of negotiations with Ukraine.
"Even if we take into account the Nord Stream, the South Stream, the Nabucco and liquefied natural gas, all the same, the shortage of gas supplies to Europe will be some 530 billion-700 billion cubic feet," he was quoted by Russia's state-run news agency RIA Novosti as saying.
Gazprom reached a recent deal with Turkish pipeline company BOTAS for South Stream. Gazprom said this week it might be cheaper to build another pipeline like South Stream than it would up upgrade the Soviet-era pipeline network through Ukraine.