Russia and Ukraine made progress on Friday toward resolving a dispute over gas supplies in time for winter, but European leaders said Moscow still has to do much more to prop up a fragile cease-fire and end fighting in eastern Ukraine.

The mooted deal could re-open Russian gas supplies to Ukraine that have been cut off since June, and ensure supply to European buyers farther west before demand surges in the cold months and stocks run down. It came as something of a surprise after talks in Milan that the Kremlin said were "full of misunderstandings and disagreements."

Russian President Vladimir Putin told reporters that a deal ensuring gas supplies "at least for the winter" had been reached after a final one-on-one meeting with Ukraine President Petro Poroshenko, which followed talks attended by European leaders.