Greece raged at neighbours and began bussing hundreds of migrants back from its northern border fearing it could be inundated with migrants halted by Balkan states trying to shut the main land route to Western Europe.
Greek police removed migrants from the Greek-Macedonian border after additional passage restrictions imposed by Macedonian authorities left hundreds of people, mainly Afghans, stuck at the border.
About 450 of them were loaded onto buses to be taken to reception centres in Athens.
. Idomeni, Greece. Reuters/Marko Djurica
Greek officials say the flow of people across the border slowed after Macedonia demanded additional identification from people seeking passage.
About 5,000 people massed at two locations in northern Greece, close to the border with Macedonia, while aid groups urged another 4,000, who arrived on the Greek mainland from outlying islands, not to head to north for fear of creating a bottleneck.
"Our biggest fear is that the 4,000 migrants who are in Athens head up here and the place will become overcrowded," said Antonis Rigas, a coordinator of the medical relief charity Medicins Sans Frontieres (Doctors Without Borders).
. Idomeni, Greece. Reuters/Alexandros Avramidis
Balkan states straddling the migrant route to western and northern Europe have begun denying passage to individuals not coming from the conflict regions of Syria and Iraq.
One migrant in his mid-30s, who said he was from the Syrian town of Aleppo, said Macedonian police did not let him cross the border because he did not have a passport.
. Idomeni, Greece. Reuters/Alexandros Avramidis
"I lost everything in the war, I have no documents," he said, declining to give his name. He said he had obtained Greek registration papers at the island of Lesbos.
Macedonia has erected a metal fence topped with razor wire at the main crossing point for migrants along its southern border with Greece.
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. Idomeni, Greece. Reuters/Marko Djurica
Migrants stand behind a border fence.
. Idomeni, Greece. Reuters/Marko Djurica
Greek policemen line up at the Greek-Macedonian border.
. Idomeni, Greece. Reuters/Marko Djurica
Migrants protest behind a border fence. The picture was taken from the Macedonian side of the border.
. Idomeni, Greece. Reuters/Marko Djurica
Migrants wait behind a border fence at the Greek-Macedonian border.
. Idomeni, Greece. Reuters/Marko Djurica
A migrants rests next to a border fence.
. Idomeni, Greece. Reuters/Marko Djurica
Migrants stand next to a border fence.
. Idomeni, Greece. Reuters/Marko Djurica
A migrant child stands behind a border fence.
. Idomeni, Greece. Reuters/Alexandros Avramidis
A migrant climbs the border fence from Greece to Macedonia.
. Idomeni, Greece. Reuters/Marko Djurica
Greek policemen encircle a group of migrants in front of a bus at the Greek-Macedonian border.
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Greek migration minister Yannis Mouzalas criticised his neighbours for shirking their responsibilities amid the crisis.
"Not only have Visegrad countries not taken in one refugee, they didn't even send a blanket or a tent," he told the TV channel of Greece's parliament, referring to the Czech Republic, Poland, Hungary and Slovakia.
They had not sent a 'single policeman' to reinforce the EU border agency Frontex either, he said.