Schengen's rules allow this "as a last resort" to avert serious threats to internal security or public policy.
Record numbers of migrants streams through the Balkans into Hungary on Thursday, forcing Austria to suspend cross-border train services as Europe remained bitterly divided over how to cope with the refugee crisis.
Schengen's rules allow this "as a last resort" to avert serious threats to internal security or public policy.
Record numbers of migrants streams through the Balkans into Hungary on Thursday, forcing Austria to suspend cross-border train services as Europe remained bitterly divided over how to cope with the refugee crisis.