European Union unity over sanctions on Russia has started to falter as jitters about the impact on Europe's own stumbling economy weakens resolve to punish Moscow for its war in Ukraine.

EU leaders agreed on Thursday to a ninth package of sanctions but talks were acrimonious, with Poland and the Baltic states that neighbor Russia campaigning for tougher measures, but states further west, such as Germany, more hesitant.

Some, such as Belgium and Greece, as well as Hungary which still relies heavily on Russian energy imports, pushed back against further sweeping measures, EU diplomats said.