Around a dozen young migrants sat waiting on a patch of grass hours after crossing the eastern border into Serbia, adding to a rise in new arrivals that is testing Belgrade's relations with its neighbours in the European Union.
After a while some of the young men slipped away from the group to the bus station in the town of Pirot and got onto coaches taking them northwest, towards the frontiers with EU members Hungary and Croatia.
Others lined up patiently when police arrived to take them to a migrant camp - one of a network of centres that aid groups say are growing increasingly crowded and targeted by people smugglers.
