"We have started today discussing the longer term, the need to reduce European dependence on Russian energy over many years to come," Hague said on Sky News after a meeting of European Union foreign ministers in Brussels.

Hague also said more names could be added to the sanctions list of 21 Russians and Ukrainians imposed by the EU.

He said the scope of future sanctions would depend on how Russia reacted to Crimea's application to join Russia following Sunday's referendum.

This is while the European stocks declined earlier after Moscow threatened Kiev to cut off its gas supply to Europe.

European equities fell 2.3 percent on March 3 after Russia’s parliament approved President Vladimir Putin’s request to send troops to Ukraine.

Ukraine is a key transit route for Russian gas to Europe. Russia says Ukraine’s natural gas debt has climbed to almost two billion dollars, signaling supplies may be cut, which would ratchet up pressure on its neighbors as they scrap over the future of Ukraine’s Crimea region.

NJF/NJF