Greek Prime Minister Alexis Tsipras has accused Austria and Balkan countries of "ruining Europe" by imposing border restrictions to slow the flow of migrants heading north from Greece. Austria angered Greece by not inviting it to a meeting of Balkan leaders in Vienna last week to coordinate a slew of border restrictions. Some 30,000 migrants are now stranded in Greece, waiting for Macedonia to reopen its border so they can continue their northward trek, mostly to Germany.