EU foreign ministers formally agreed to prolong to January 2016 damaging economic sanctions against Russia to ensure it fully implements Ukraine peace accords.
European Commission chief Jean-Claude Juncker voiced frustration with Greek Prime Minister Alexis Tsipras in a media report amid the deepening debt crisis.
IMF chief Christine Lagarde warned that a resolution to five months of tortuous debt talks with Greece required "adults in the room" in an apparent sideswipe at Greek officials.
Greek Prime Minister Alexis Tsipras called European Commission chief Jean-Claude Juncker, their first contact on the stand-off over a bailout deal since last week.
Greece's creditors piled pressure on cash-strapped Athens as the IMF pulled its team out of talks and the EU warned Athens to stop gambling with the possibility of default.
The EU's Economic Affairs Commissioner Pierre Moscovici said he believed "more than ever" that a debt deal was possible between Greece and its creditors.
Greek Finance Minister Yanis Varoufakis warned that EU leaders had a duty to avoid a historic "failure" and urged a swift accord in Greece's debt talks with its creditors.
Prime Minister David Cameron was put on notice that 50 of his own backbenchers will lead calls for Britain to quit the EU if he does not secure major concessions from Brussels.
European Commission head Jean-Claude Juncker said that "challenging" negotiations with Greece would continue, after late-night talks with premier Alexis Tsipras broke up without a deal.
European parliament head Martin Schulz said the Russian ambassador to the EU was barred access to the institution in retribution for a travel ban imposed by Moscow.
Britain could lose its prized EU veto on some subjects if it opts out from the commitment to "ever closer union" in the bloc's treaties under David Cameron's reform plans.