Violent protests broke out as tensions ran high at the border of Macedonia and Greece following a two-day blockade by migrants prevented from crossing.
An estimated 3,000 Pakistani, Moroccan and Iranian migrants have been trapped in no-man's land between the two countries for several weeks, after non-EU Balkan countries began restricting entry to certain nationalities.
With Greek police on one side and Macedonian forces on the other, migrants have been forced to sleep in small, thin tents in near-freezing temperatures.
Officers from Macedonia - which has begun installing a metal fence along the border - fired tear gas at protestors after being pelted with rocks and stones. Frustrated migrants even tried to storm the border to enter Macedonia at one point.
Several hundred migrants blocked the crossing earlier in the week, but began letting families through again yesterday evening.
One Iranian migrant, who gave his name as Hamid, said they were angry that they were being kept out while those from Afghanistan, Iraq and Syria were classed as refugees and were being let through because they were escaping conflict.
More than 800,000 people have arrived in Europe from the Middle East and Africa so far this year, many of them making the treacherous journey across the Mediterannean Sea in flimsy dinghies.
Thousands have died on the crossing, but many have been rescued by the coastguards of Greece and Italy.
Today alone, rescuers pulled almost 2,000 migrants from 11 boats off the Italian coast - the largest rescue figure in more than a month, as the steady flow of boats has slowed somewhat in recent weeks due to the bad weather.