Stranded migrants have lay with their children on rail tracks at Greece's northern border, demanding to be allowed to continue their journey, as Germany warned that Europe cannot let the country "plunge into chaos".
Tensions between European nations worst affected by the migrant crisis are running high, with Austria's Chancellor Werner Faymann accusing Greece of "behaving like a travel agency" for migrants hoping to start new lives elsewhere in Europe.
But after Balkan countries this week announced a daily cap on migrant arrivals, Athens warned that the number trapped in Greece could soon be in the tens of thousands, as refugee boats continue to land on Greek beaches from Turkey every day.
"We estimate that in our country the number of those trapped will be from 50,000-70,000 people next month," Greek Migration Minister Yiannis Mouzalas said in an interview with Mega TV, up from 22,000 at present.
German Chancellor Angela Merkel said Europe could not allow debt-crippled Greece to plunge into "chaos" by shutting countries' borders to refugees, just months after Athens' third huge international bailout.
"Do you seriously believe that all the euro states that last year fought all the way to keep Greece in the eurozone -- and we were the strictest -- can one year later allow Greece to, in a way, plunge into chaos?" she said in an interview with public broadcaster ARD.
Some 6,500 remained stuck in a camp at Idomeni on Greece's border with Macedonia, unable to move on after Macedonia and Serbia, as well as EU members Slovenia and Croatia, imposed a daily limit of 580 migrant entries.
Several hundred migrants staged a protest at the border on yesterday, sitting and lying with their children across the train tracks.
Some held up handwritten posters that read "Open the borders, no food" and "We are humans, not animals".
"I'm 17 days on the road with my family and my two children. I don't know what to do," one Syrian man told Athens News Agency as he lay across the tracks with his children.
The build-up at the Idomeni camp, which can hold up to 1,500 people, began in earnest last week after Macedonia began refusing entry to Afghans and imposed stricter controls on Syrians and Iraqis.
The Balkan clampdowns come hot on the heels of a move by Austria, further up the migrant trail to Germany and Scandinavia, to introduce a daily cap of 80 asylum applications and a limit of just 3,200 migrants transiting through per day.
