Updated

German Chancellor Angela Merkel is joining Western Balkan leaders for a summit focused on migration, anti-extremism and regional cooperation.

The meeting on Thursday will also be attended by EU foreign policy chief Federica Mogherini. Already in Vienna are the government heads of Albania, Bosnia and Herzegovina, Kosovo, Macedonia, Montenegro and Serbia, along with other government ministers from those EU-aspirant countries.

Many of the migrants entering the European Union use the so-called Balkan route, leading through Macedonia and Serbia into Hungary and then to Austria, Germany and other EU nations to the west.