Germany cut its train-link with the Austrian city of Salzburg on Wednesday, shutting down the main route into its territory for tens of thousands of people caught in Europe's worst migration crisis in decades.
Around 1,200 migrants slept overnight at Salzburg station on camp beds set up in the car park. Many more stayed in emergency accommodation across Austria, part of a massive backlog waiting for transport on to Germany.
Germany announced border controls on Sunday that have slowed a rush of people over its border, relieving pressure on officials who have struggled to cope with the influx.
But the numbers of people waiting in Salzburg and other cities have strained resources in Austria.
"We had more than 2,000 refugees an hour ago. The station was about to be closed," Wilfried Haslauer, the governor of Salzburg province, said on Wednesday morning.
"Now the refugees have understood that no trains are running, and they are setting off on foot."
Hundreds of people remained at the station, a Reuters witness said, but city officials said several hundred were walking towards the nearby border.
"We have only observed small groups and we have seen no people on the tracks," a police spokesman said.
Rail traffic between Germany and Salzburg was halted in both directions on orders of the German authorities, a spokeswoman for the Austrian rail operator OeBB said, adding that no details on the reason for the closure were immediately available.
A rush of people into Austria - almost all of whom hope to reach Germany - has also slowed to a trickle since Tuesday, when Hungary barricaded its southern border against migrants trying to cross its territory.
Signal to the World
Austria introduced stricter border controls of its own on Wednesday, following Germany's lead.
Both moves have effectively suspended a system of borderless travel within Europe known as Schengen, but Vienna has made clear that the checks will slow migrants rather than stop them altogether.
"These border controls should be an important signal to the world," Interior Minister Johanna Mikl-Leitner told the broadcaster ORF late on Tuesday. "There can be no borderless flow of migrants."
Austria and Germany have called for a European leaders' summit to address the migration crisis, Europe's worst since the war in the Balkans in the 1990s, and called for quotas for the redistribution of asylum seekers within the bloc, combined with stricter measures near its external border.
The proposals have faced opposition from Eastern European countries.
"At the moment, more than 2,000 are coming (into Germany) with normal train services," Austrian Chancellor Werner Faymann told ORF on Wednesday morning. "But if 25,000 or 22,000 people are in emergency accommodation, then you see that a bottleneck has arisen from the controls."
In the eastern province of Burgenland, which borders Hungary, a police spokesman said the border controls had started, but he confirmed that migrants arriving at Austria's eastern border would not be denied entry.
"The police have set up a funnel here to obviously slow down the speeds and to selectively choose vehicles which fall into the inspection mechanism and inspect them," a spokesman for the police in Burgenland said. "I'm sure no one will be sent back."