The buildup began last week after Macedonia began refusing entry to Afghans and imposed stricter document controls on Syrians and Iraqis, slowing the passage of migrants and refugees to a trickle. The situation is set to worsen after Slovenia and Croatia, both EU members, and Serbia and Macedonia said on Friday they would restrict the number of daily arrivals to 580.

The tighter controls have left thousands stranded in Greece, as Europe’s worst refugee crisis since the second world war shows no sign of abating.

By Saturday, some 5,500 people were stranded at Idomeni, police said, with another 800 gathered at a provisional camp about 12 miles (20km) away.

Since Thursday night, only 150 people had crossed north into Macedonia, officials said, putting the total number of refugees and migrants in Greece at about 25,000.

Tensions were running high at the border, with about 400 people protesting by the Idomeni crossing early on Saturday, demanding that the Macedonian authorities let them in.

Austria said last week it would only allow 80 people a day to claim asylum, and would limit the daily number of people crossing the country to 3,200.

The move has sparked a bitter spat between Athens and Vienna, with Greece fearful it would trigger a domino effect, leaving thousands stranded on its territory.

Austria has repeatedly accused Greece of failing to police its borders properly and allowing an excessively high number of people to continue their journey northwards to western Europe.

Last week, the EU told Austria that limiting asylum claims was “plainly incompatible” with European and international laws.

The Greek president, Prokopis Pavlopoulos, said on Saturday: “Europe can’t be indifferent to those of our partners who don’t respect their obligations.”

The country’s prime minister, Yiannis Dragasakis, had said a day earlier that Greece was not prepared to become “the subsidised border guards of Europe”.

In an attempt to regulate the flow of refugees until the border situation is resolved, Greek authorities are trying to house them on the islands where they land after crossing the sea by boat from Turkey.

On Saturday morning, another 437 people landed in Pireaus port, according to one report.

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