Ukraine's Energy Ministry does not recognize the USD 3.5 B sum which Russian concern Gazprom says Naftogaz owes for gas supplies.

Yury Prodan, the Ukrainian Energy Minister, was quoted by RBC Ukraine as saying that Kiev will calculate its debt only under "market prices".

On Wednesday, Prodan declared that Ukraine was ready to deliver on its liabilities to Gazprom if the pricing regime used for gas supplies until April 1, or USD 268.5 per 1000 cubic meters, is restored. Russian government officials however denied the request.

Price reductions were agreed between Russia and Ukraine in both 2010 and 2013, but a bitter dispute emerged in the month following the Maidan revolution and the ousting of President Viktor Yanukovych. Gazprom then said it was introducing a new regime for gas deliveries and announced a severe hike in April, pushing prices up over 80% to USD 485 for 1000 cubic meters.

In Central Europe, the "market price" for gas is currently somewhere between USD 350 and 400 for that quantity, but Prodan is adamant that the previous amount, USD 268.5, is commercially determined.

EU leaders have long expressed concern that a repetition of Russia and Ukraine's 2009 gas dispute amid the ongoing the Kiev-Moscow standoff might again jeopardize supplies to Europe.