The number of migrants stranded on the Greece-Macedonia border continued to swell on Monday, footage from an aerial drone showed.
Rows and rows of tents could be seen dotted for kilometers among the vast fields at the border, along the railway tracks and station, and around the main roads.
The camp was flooded with pools of water and mud from recent rains.
Greek police officials said only 337 passed in the last 24 hours.
At least 12,000 migrants are camping out on the border, which rarely opens to allow people through.
Greece estimates 30,000 are gathered in the country as a whole.
EU leaders and Turkey will meet on Monday, in a last-ditch attempt to stem the massive movement of people across the continent.
Austrian Chancellor Werner Faymann has urged Germany to set a clear limit on the number of asylum seekers it will accept to help stem a mass influx of refugees that is severely testing European cohesion.
Greece will press for solidarity with refugees and fair burden-sharing among European Union states at Monday's emergency EU summit with Turkey.
While German Chancellor Angela Merkel said in a media interview published on Saturday that Greece needs to deliver quickly on its promise to provide accommodation for 50,000 refugees and the European Union should help Athens with this task.
It is expected that leaders will discuss the closure of the Balkan route through Greece for the migrants, affecting the thousands on the Greece-Macedonia border.