IDOMENI, Greece -- A group of migrants at Greece's border with Macedonia blocked a rail line Thursday in protest at Macedonia's refusal to let them in to continue their route toward Western Europe.

The group lay down on the Greek side of the train track, preventing a freight train that had just crossed from Macedonia from continuing its journey south.

Some 10,000 people are blocked at the border. Macedonian authorities have said they will only let in as many people as the next country on the route, Serbia, takes. Greek police said that in the 24 hours to 6 a.m. Thursday, 500 people were allowed to cross.

Some of those, however, were then turned back by Macedonian authorities who said their papers were not in order. One man fainted after he was turned back.

The migrants said Macedonia did not accept computer-generated stamps issued by the Greek police, and therefore they could not prove their identity documents are genuine.

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Adnan Abdallah from Syria had waited to cross from Greece to Macedonia for three days, but when he finally was let through, he was turned back because the stamp on his refugee document is computer-generated.

"They say here (in Greece) everything is OK, but on the other side this is not acceptable," a frustrated Abdallah told The Associated Press.