Europe could soon explode into uncontrollable and widespread violence because of the refugee crisis.


That warning comes from UNHCR, or the United Nations High Commissioner for Refugees.


The agency reports that 24,000 refugees and migrants in Greece need shelter. This includes about 8,500 people near the border with Macedonia. It says there are shortages of food, shelter and water. It says the areas are unclean.


Vincent Cochetel is the top representative of UNHCR in Europe. He says migrants and refugees fleeing the Balkans are stopped at border crossings. He says they do not understand that they cannot flee to other countries.


Cochtel says those countries must first permit refugees to enter. Not all of the refugees will get permission, he says.


There is “a lot of frustration building up, which may lead to acts of violence,” he says.


A peaceful protest Monday near the Macedonian border became violent when police used tear gas to force refugees and migrants to move away from a border fence.


Almost 132,000 people have crossed the Mediterranean Sea this year. Half of them are women or children. That is more than the number who made the dangerous journey in the first six months of 2015. Almost all of them have landed in Greece.


UNHCR spokesman Adrian Edwards says the European Union must move forward with the plan it agreed to last year to settle the refugees equally among its 28 members.


“It should concern everyone that despite commitments to relocate 66,400 refugees from Greece, states have so far pledged only 1,539 spaces, and only 325 actual relocations have occurred,” he said.


The UNHCR says Greece must quickly increase its ability to care for the large number of people that are entering the country. And it said the EU member states must work together more closely.