In Brussels, US Secretary of State John Kerry and the EU’s top diplomat Catherine Ashton have met for high level talks on energy.

The summit was dominated by the simmering Ukraine crisis and came a day after Moscow imposed a hefty price hike on natural gas to Kyiv.

Kerry said the US and Europe were taking important steps to stop individual countries from holding others hostage over energy.

Kerry said: “No nation should use energy to stymie a people’s aspirations. It should not be used as a weapon. It is in the interest of all of us to be able to have adequate energy supplies critical to our economies, critical to our security, critical to the prosperity of our people.’‘

His warning follows yesterday’s move by Russia’s Gazprom to increase the price of its natural gas for Ukraine by more than a third.

That came after a discount, agreed by Ukraine’s ousted President Victor Yanukovych, came to an end.