“Profiling asylum seekers on the basis of their alleged nationality infringes the human right of all people to seek asylum, irrespective of their nationality and to have their individual cases heard,” Ban said in a statement attributable to his spokesperson on the latest reaction to the huge influx of hundreds of thousands of people fleeing fighting in their homelands.

Under restrictions imposed last week at borders between Greece and the Former Yugoslav Republic of Macedonia and between the latter and Serbia, only Syrians, Afghans and Iraqis are being let through while others, including Iranians, Bangladeshis and Pakistanis, are being blocked.

“The Secretary-General calls on all States in the region to respond effectively to the mounting humanitarian challenges and to ensure that their policies on screening asylum seekers are in line with international refugee and human rights law,” the statement said.

“He urges European governments to significantly improve their capacities for reception and to speed up implementation of the relocation programmes for refugees. He recalls that collective expulsion and refoulement are strictly prohibited under international law,” it added.

The statement called on all States in the region to respond with compassion, solidarity and shared responsibility, noting that the current situation highlights the urgent need for coordinated border management.

Also on Tuesday, just days after warning that the restrictions are endangering refugees and migrants, especially children, the Office of the UN High Commissioner for Refugees (UNHCR), voiced renewed alarm as the harshness of winter looms that human traffickers are waiting to take advantage of the chaos.

“With refugees and migrants expected to continue arriving in Europe via Greece over the winter and into 2016 it is imperative that the situation be managed in such a way as to minimize the risks of new problems being created,” UNHCR spokesperson Adrian Edwards, told a news briefing in Geneva.

“All people have the right the right to seek asylum, irrespective of their nationality and to have their individual cases heard,” he said, calling for proper information, counselling and accommodation to be provided.

He said the restrictions will play into the hands of human traffickers as people seek alternatives to the current chaos. “As we head into winter, stabilization and proper and comprehensive management of Europe’s refugee and migrant situation remains urgently needed,” he stressed.

Last Friday, UNHCR joined the UN Children’s Fund (UNICEF) and the International Organization for Migration (IOM) in issuing a joint statement warning of the dangers to blocked refugees and migrants as the bite of winter takes hold, and calling on Governments to provide more reception centres and decent accommodation.

“This is becoming increasingly untenable from every point of view – humanitarian, legal, and also safety related, not least in light of falling temperatures and the risks for children and others with specific needs,” Edwards said then.

About 150 people have returned voluntarily over the past 48 hours to the Greek capital of Athens where they are being advised that they can seek asylum, the spokesperson said on Tuesday.