Ministers from Austria and Western Balkan countries were set to meet in Vienna Wednesday to coordinate their increasingly restrictive immigration policies in the face of criticism from Brussels and Athens.
Austria put in place daily entry quotas for refugees late last week, triggering restrictions in countries along the Balkan migration route, all the way back to the Greek-Macedonian border.
Interior and foreign ministers were set to gather in the Austrian capital to discuss issues such as border management and fighting people-smugglers, as well as improving information about their policies in countries of origin.
The Vienna conference would also serve to create unified positions ahead of Thursday's meeting of EU interior ministers in Brussels, an official close to the talks told dpa.
Austria invited ministers from Albania, Croatia, Bosnia and Herzegovina, Bulgaria, Kosovo, Macedonia, Montenegro, Serbia and Slovenia.
Greece has sent a protest note to Vienna, complaining that the assembled ministers are failing to consult Athens.
Macedonia's new policy of denying entry to Afghans - one of the major migrant groups - has already caused a large backup on the Greek side of the border.
The European Commission has also criticized the restrictions along the Balkan route as unlawful and running counter to an EU-wide approach.