Greece has recalled its ambassador in Vienna after Austria excluded it from a meeting of Balkan states on Europe's migrant crisis.
The move to recall the envoy for consultations was designed to "safeguard friendly relations between the states and the people of Greece and Austria", a statement from the ministry said.
Ten Balkan states meeting in Austria on Wednesday agreed to coordinate action to limit the migration flow along their countries.
As well as triggering a domino effect of national border controls limiting the flow of people northwards, their decision has left thousands stranded in Greece, the main gateway for those fleeing upheaval in the Middle East and beyond.
"Unilateral initiatives to solve the refugee (crisis) and violations of international and European laws by EU member states is a practice which would undermine the very foundations of European unification," the Greek ministry said.
"Responsibility for dealing with the migration and refugee crisis cannot burden one country."