The European Commission, the executive body of the European Union (EU), has expressed deep concern about police brutality against refugees trapped on the Greek-Macedonian frontier.
"The commission is very concerned by the images we saw yesterday," European Commission spokesman Margaritis Schinas told a press conference in the Belgian capital city of Brussels on Tuesday.
The remarks came one day after Macedonian police used teargas to disperse some 300 refugees, who had forced their way through a Greek police cordon and raced toward a railway track between the two countries.
Asylum seekers have become stranded in Greece after Austria and some Balkan countries such as Macedonia imposed restrictions on their borders, limiting the numbers able to cross.
An estimated 24,000 refugees have been camping in squalid conditions with little food or medical help on the Greek side of the border as Macedonia is letting very few in.
"The images show once again that the only solution is a collective solution, a European solution," Schinas said, adding, "All measures on the borders must be in compliance with international law, and European law."
UNHCR warning on refugees' situation
In another development on Tuesday, the United Nations High Commissioner for Refugees (UNHCR) announced that over 131,000 asylum seekers have reached Europe via the Mediterranean so far this year, more than the total number recorded in the first half of 2015.
Warning that the build-up of refugees at Greece's northern borders risks creating a humanitarian disaster, the UNHCR called for better accommodation for those stuck in Greece.
"Europe is on the cusp of a largely self-induced humanitarian crisis," UNHCR spokesman Adrian Edwards told a news briefing in the Swiss city of Geneva, adding, "The crowded conditions are leading to shortages of food, shelter, water and sanitation."
Europe is facing an unprecedented influx of refugees, most of whom are fleeing conflict-ridden zones in Africa and the Middle East, particularly Syria.
Many blame the support by some Western countries for militants operating in the Middle East as the main reason behind the refugee influx into Europe.