Belgrade -- more vulnerable than adults, exposed to smugglers and violence, and they do not know how to protect themselves - children make up a third of the refugees seeking their way to Europe.

The most vulnerable among them are those who are travelling without their parents, usually in a group of peers or accompanied by unknown people.

Belgrade (dpa) - Organized crime - along with a variety of schemes exploiting vulnerable people - will be the main beneficiary of recent decisions to seal borders and keep migrants from crossing the Balkans, international aid workers warned Wednesday.