Hundreds of people have begun arriving in Slovenia after Hungary closed down its southern border with Croatia to refugees.
Slovenian police said five buses carrying 300 refugees entered the country on Saturday through checkpoints with Croatia.
Officials said they would be registered before continuing their journey to Austria and Germany, the preferred destination of the vast majority, many of them Syrians fleeing war.
The latest episode in Europe's ongoing crisis came as Hungary's right-wing government declared its southern frontier with Croatia off limits to refugees, blocking entry with a metal fence and razor wire just as it did a month ago on its border with Serbia.
Croatia responded to the move by directing refugees west to Slovenia, the Reuters news agency reported.
Hungary also said it had reinstated border controls on its frontier with Slovenia, effectively suspending Europe's Schengen system of passport-free travel though it said it was acting within the Schengen rules. Both Slovenia and Hungary are part of the Schengen Area while Croatia is not.
Aid agencies are concerned about backlogs of people building in the Balkans, battered by autumn winds and rain as temperatures drop before winter.
A government spokesman said Budapest had taken the step because "migrants appeared" on the Slovenian side of the border.
Hungary says it is duty-bound to protect the borders of the European Union the refugees, most of them Muslims who Hungary says threaten the prosperity, security and "Christian values" of Europe.
With several other ex-Communist members of the EU, Hungary opposes a plan by the bloc to share out 120,000 refugees among its members.
That is only a small proportion of the 700,000 people expected to reach Europe's shores by boat and dinghy from North Africa and Turkey this year, many of them fleeing war and poverty in the Middle East, Africa and Asia.
Source: Reuters And Al Jazeera