Serbia has arrested 16 people suspected of trafficking refugees from the Middle East, Asia and Africa, as part of increased efforts to stem the flow of illegal migrants trying to reach Western Europe, the interior ministry said on Thursday. In a statement, the ministry said all 16 suspects detained by police and state security agents came from the southern towns of Presevo and Bujanovac, just outside Macedonia. Serbia was at the center of last year's migrant influx into Europe, when hundreds of thousands of people fleeing war in the Middle East journeyed up through the Balkans to reach sanctuary in the European Union.