Updated

The European Union and the United Nations on Tuesday criticized new police restrictions that can block Afghan asylum-seekers from traveling along main migrant route through the Balkans into Western Europe.

Police chiefs from EU nations Austria, Croatia and Slovenia plus non-members Serbia and Macedonia agreed last week to only allow in people "arriving from war-torn areas."

They decided migrants must carry identity documents, be fleeing a conflict zone and have a "registration form issued by Greek authorities." The new rules block entry for people wanting to reunite with families, avoid military recruitment or escape "personal disputes."

"(We) have concerns about this approach, and will raise the matter with the relevant countries," the EU's executive arm said in a statement.

The move has stranded thousands of Afghans and others in Greece, where an average of 4,000 asylum-seekers land each day.

The UN's refugee agency said the new police orders are "resulting in increased protection risks for refugees and asylum-seekers, particularly those with specific needs, such as unaccompanied and separated children."

It said the measures increased the risk that legitimate asylum-seekers could be turned back or "stranded in the open, exposed to freezing cold weather and at risk of violence and exploitation."

In recent days, thousands of Afghan migrants have been have been blocked from moving from Greece into Macedonia even though they could potentially qualify for asylum.

Earlier Tuesday, Greek police removed hundreds of migrants from a camp at Greece's border with Macedonia following a protest that halted freight rail services to other Balkan countries. Authorities said the mostly Afghan migrants were being put on buses bound south for Athens. Journalists were refused access to the area.

The Czech Republic's prime minister, meanwhile, said the 28-nation EU should stop migrants from using the Balkans route if Turkey and Greece aren't doing enough to stop them from coming in.

The Czech Republic, Hungary, Poland and Slovakia support creating a new barrier on Greece's borders with Macedonia and Bulgaria. But the EU — led by Germany — fears that the move would overwhelm Greece, where more than 850,000 people landed and passed through last year.

More than 100,000 people have already entered Greece so far this year.