Hungarian officials have arrested the first people breaking strict new border rules that were introduced at midnight.
Three men, believed to be Syrian, were detained early on Tuesday for illegally crossing from Serbia into Hungary under a wire fence at the border town of Roszke.
The new laws make it a criminal offence, punishable by prison or deportation, to damage Hungary's newly erected border defences.
A small number of refugees were allowed into Hungary via the heavily guarded crossing at Roszke on Tuesday morning.
