Macedonia has introduced strict border controls, saying it's trying to separate economic migrants from refugees fleeing war. The result is thousands of asylum seekers who are now stranded in Greece, a country that has allowed migrants to pass through, but does not want them to stay.
Outside the Greek border town of Idomeni, privately-chartered buses drop off migrants who have made it across Greece with plans to seek asylum further north in Europe.
But they soon reach a new barbed wire fence that Macedonia has erected along its border to block the influx. It's a babel of languages, with people speaking Arabic, English, Farsi and Greek as they wait near the border fence.
Shaid Olahan, dressed in a brown parka and shivering in the biting wind, says he's an Afghan. The Macedonian policy is to allow through people from Afghanistan, Syria and Iraq since those countries are at war.
But in practice, it doesn't always work that way. A Macedonian border guard turns Olahan back after seeing his identity card.
"He told me, 'Your document is no good. With this you go back,'" said Olahan. "Yeah, he doesn't believe my document."
A United Nations worker asks Olahan about the card and a transit document issued by the Greek police. Both documents are photocopies, not originals.
"Where did you get this document from? From police? Are you sure?" the worker asks Olahan.
Then a Greek policeman speaks to him and several other migrants who have been turned away. They include a family who says they're from Iraq — but don't have IDs or registration papers issued by Greek authorities.
Just a couple of days ago, more than 2,000 migrants rejected by Macedonia camped out here in tents. They included Moroccans, Iranians, Pakistanis and Somalis. They hoped the border would open.
They camped out for two weeks, growing increasingly frustrated. Some blocked passage to Syrians, Afghans and Iraqis, saying if they couldn't pass, no one could. There were protests and fights.
Alireza Akhondi, a Swedish-Iranian politician, volunteers here. He watched some of his fellow Iranians sew their lips shut to protest being shut out of Macedonia. He watched migrants turn on each other.
"And the reason is lack of hope," he says. "I don't see any hope. We did see that before...in the summer. ... But now, I look in people's eyes and only see desperation."
On Wednesday, the Greek police cleared everyone out and bused them back to Athens.
Macedonia treats everyone as an economic migrant — which means they are barred from entering — unless they can prove they are refugees from one of the three war-torn countries.
Lake Karaoghlan, 17, from Somalia waits at a highway rest stop near the border. He's traveling with several fellow Somalis who say they fled the Islamist extremist group known as al-Shabab.
"They're gonna kill you. Without reason," he says of al-Shabab.
His friend, Mahmoud Ahmed, is just 15.
"We feel bad. And they're saying you are economic immigrant. But there is ... there is a war," Ahmed says of Somalia.
Al-Shabab tries to recruit boys. "And the government thinks all boys are in al-Shabab," Ahmed says. "We can't win."
At the same rest stop, Ismail Shinwari reads a pamphlet in English about the Bible. A Jehovah's Witness gave it to the 22-year-old Afghan at a refugee camp on the Greek island of Lesvos, where he landed a little over a week ago after crossing the sea from Turkey.
"I have run out of things to read," says Shinwari, who's trying to get to Belgium and finish his business administration degree.
He's smiling and relaxed; with his Afghan passport, he knows he can cross the border.
But the man sitting next to him, a Pakistani man who gives his name as Ali Qadri, looks worried.
Qadri is 32 and doesn't have a passport on him. He speaks very good Greek and claims he learned it in Pakistan. But he sounds like he may have lived in Greece as an economic migrant for many years.
He says he's going to tell the Macedonians he's from Afghanistan.
"It's a lie, I know. But I have to try to get past that border," he says.
Chances are, Qadri won't get very far. He will likely get sent back on a bus to Athens, to an abandoned arena that was built for the 2004 Olympic Games. That's where Greek authorities are housing the thousands of migrants now stuck in the Greek capital.