Hundreds of migrants and refugees are beginning to arrive at the Austrian border after Hungarian authorities laid on buses to carry them there.
Austria and Germany have both said that they will grant them access, regardless of European Union rules which are meant to restrict the movement of unregistered migrants.
Hungary's decision to transport people to the border followed days of chaos in the capital Budapest, which resulted in more than a thousand attempting to get there by foot.
The crowd was led by a one-legged Syrian man as it travelled along the main highway to Vienna, and could be heard chanting "Germany, Germany!"
More than 140,000 migrants have been recorded entering Hungary so far this year through the EU's external border with Serbia, and the decision to aid thousands in reaching Austria marked an embarrassing climbdown for the country's right-wing government.