Morawiecki -- whose nationalist government clashed with Timmermans in recent years over backsliding on the rule of law in the EU's largest ex-communist state - said differences between the bloc's national leaders were still very wide and a deal was not certain when they reconvene on Tuesday.

Morawiecki said reaching compromises was key as the EU elects its next leadership and that such a momentous decision should not be forced on reluctant countries as that would undermine the bloc's future cohesion.