Russia is putting energy security in Europe at risk by increasing the price it charges for natural gas, the Ukrainian energy minister said.

Russian energy company Gazprom in 2009 cut gas to Ukraine because of contractual disputes. The row left downstream consumers in Europe in the cold because, while Europe gets about a quarter of its gas from Russia, the majority of it runs through the Soviet-era transit system in Ukraine.

Ukrainian Energy Minister Yuriy Prodan said a decision by Gazprom to cancel a gas price discount for Ukraine left it with some of the highest natural gas bills in the region.

"In this situation, the threat of cutting gas deliveries to Ukraine arises, as well as the threat of cutting transit gas to Europe because Ukraine's ability to support the transit is not unlimited," he said Tuesday.

Prodan said the price increase was unfair and had nothing to do with market factors.

The 2009 disruption prompted European officials to look for alternate gas supplies to break Russia's grip over the region's energy sector. Simmering tensions over Ukraine have reinvigorated the effort, with U.S. officials saying shale natural gas could provide a layer of energy security in the form of liquefied natural gas.

[RIA Novosti]