Polish Prime Minister Donald Tusk has denounced as "unacceptable" Germany's decision to extend temporary controls to all its land borders as part of its response to irregular migration.
He is one of several figures from neighbouring countries to criticise the move. Restrictions already in place at some of Germany's land borders will apply from next Monday with France, Belgium, the Netherlands, Luxembourg and Denmark.
The head of a Dutch-German alliance of border communities said it was a "panic reaction", while Austria's interior minister stressed it would not be take in anyone turned away by Germany.
However, Germany's opposition conservatives said Berlin had not gone far enough.