A migrant rests as a Macedonian policeman stands guard at the Greek-Macedonian border, August 21, 2015. Macedonian police firing tear gas drove back crowds of migrants and refugees trying to enter from Greece on Friday, enforcing an emergency decree sealing the frontier to thousands of Syrians, Afghans and others trying to reach western Europe. The Balkan country declared a state of emergency on its northern and southern borders on Thursday after weeks of chaotic scenes at a border railway station inundated daily by up to 2,000 migrants and refugees crossing from Greece en route to Hungary and Europe's borderless Schengen zone. REUTERS/Alexandros Avramidis