Migrants and refugees arriving in Greece must state their final destination to travel further into the European Union, a Greek police source told Reuters on Thursday, following moves by neighbouring states to quell migrant flows.
Serbia on Wednesday said it would deny migrants access to its territory unless they planned to seek asylum in Austria or Germany.
"As of today, the final destination – as stated by the migrants – will be registered in the official documents," the official said without disclosing the reason for the decision.
It was not clear whether the refugees would be banned from travelling further depending on their final destination. But most migrants were expected to state Austria or Germany, refugee agency officials said.
Greece, a main gateway to Europe for migrants crossing the Aegean sea, has faced criticism from other EU governments who say it has done little to manage the flow of hundreds of thousands of people arriving from Turkey on its shores.
Austria wants to cap the number of people it allowed to claim asylum this year at less than half last year's figure, it said on Wendesday. It has said it would bar all migrants intending to pass through its northern neighbour Germany to other western European countries.