Records have again been broken for the number of migrants flooding into Europe.
In Serbia more than 3,200 arrived from the Former Yugoslav Republic of Macedonia on Wednesday.
Meanwhile Hungary plans to reinforce its southern border with mounted police and dogs.
The country, which is part of the Schengen passport-free travel zone, is building a three-and-a-half-metre high fence along its border with Serbia.
Prime Minister Viktor Orban has taken a hard line.
He calls the migrants a “threat to European security, prosperity and identity.”
Critics say Hungary’s attempts to keep migrants out is futile:
Authorities say 140,000 have crossed from Serbia to Hungary so far this year, though many more could have passed unnoticed.
The migrants mostly come from Syria, Afghanistan and Pakistan from where they are fleeing conflict and poverty:
Almost all of them hope to reach more affluent countries in the north and west of Europe such as Germany and Sweden.
Germany is expecting 800,000 to arrive by the end of this year.