Leaders along the Western Balkan migratory route pledged not to let the influx repeat this year ahead of a migration summit in Vienna on Saturday, September 24. They saw one million people pass through last year on the way to Germany and northern Europe. Austria’s chancellor, Christian Kern, urged joint EU action to tighten Europe's external borders and send aid to countries where most migrants leave from. "There is now an understanding in the European Union that we have to stop the flow of illegal migrants, and that we need border controls at our external borders," Kurz said.