Naftogaz and Russian energy monopoly Gazprom signed a deal to end a disruptive pricing dispute in January whereby the Ukrainian gas transit company would pay $450 per 1,000 cubic meters of natural gas.
"I'm sure that those who have signed this agreement and accepted these terms will have to answer for their actions," Ukrainian President Viktor Yushchenko said.
Ukrainian Prime Minister Yulia Tymoshenko had said earlier that the annual price for natural gas would be closer to $228.
Yushchenko slammed the terms of the deal, saying $450 for natural gas was "exorbitant," RIA Novosti reported.
Ukraine initially had rejected an offer by Gazprom to sign a deal for gas at $250, with Gazprom raising that price to $450 in response. Earlier contracts for Ukraine offered gas at a significant discount.
Russia disrupted gas supplies to Europe via Ukraine following a dispute over 2009 contracts and outstanding arrears. Nearly 80 percent of the Russian natural gas bound for Europe travels through Ukraine.
Tymoshenko told the delegation at the 45th Munich Conference on Security Policy, however, the dispute would not tarnish her country's reputation as a viable transit country.