Updated

U.S. Secretary of State John Kerry is denouncing the use of energy as a weapon, a day after Russia sharply hiked the price for natural gas to Ukraine.

Kerry says supplies of oil and gas have to be secured throughout the world in order to prevent their being used as political leverage or tools of aggression. He said no nation should be able to use energy to "stymie a people's aspirations."

Kerry spoke Wednesday at a meeting of the US-EU Energy Council at European Union headquarters in Brussels.

Russia also threatened to reclaim billions in previous discounts for Ukraine, raising the heat on its cash-strapped government. The move is expected to eventually hit Ukrainian consumers hard. Household gas prices in Ukraine are set to rise 50 percent beginning May 1.