Thousands of refugees are suddenly stranded along the Greek-Macedonian border on Tuesday after Macedonian officials passed new restrictions blocking their passage north.

As many as 8,000 are trapped along the frontier, as well as at the port of Piraeus. Macedonia's response is due to the knock-on effect of countries to the north either closing their borders or otherwise restricting the flow of refugees that can pass through.

Macedonian police said they were limiting Afghans "because Serbia, Croatia and Slovenia decided to reduce their number."

But Austria's decision to limit itself to 80 asylum seekers per day, while waving through another 3,200 refugees, mostly bound for Germany, has also contributed to the problem, and was called “unacceptable” by Germany's Interior Minister Thomas de Maiziere.

The move was also prompting countries to the south to begin allowing the passage of refugees through their own borders. Austria is now planning its own mini-summit with its Western Balkan neighbors on Wednesday.

Austria's new "unilateral actions" were unanimously opposed by EU leaders meeting in Brussels late last week.

While there is now growing concern about what will happen in Greece – as refugees are beginning to accumulate there - the EU and Turkey are due to hold a special summit in early March in an effort stem the migration crisis.

But in recent days, more than 600 Afghan refugees have been sent back to Macedonia from countries to the north.

"We can't allow Macedonia to become a buffer zone and refugee camp," said a foreign ministry official, declining to be named.

Desperate Afghan refugees are blocked from crossing the Greek-Macedonian border at Idomeni

Desperate refugees

Desperate to get through the Greek-Macedonian border the refugees held signs that read: "We can't go back" and "Why racism?" while dozens of Afghan children also carried signs with the words: "Help us cross the border."

Some 1,200 are stranded at the Idomeni border crossing alone, after unsuccessfully attempting to push their way through to Macedonia. The also squatted on rail lines Monday, protesting the additional crossing restrictions.

Before dawn on Tuesday Greek police surrounded about half the migrants with a caravan of empty buses, according to a Reuters source on the Greek side of the border.

The overwhelming majority were either Afghans or people without proper travel documents. But with Macedonian authorities demanding additional documentation, including passports for those trying to enter the country, the migrants' path is being blocked.

But the flow of refugees continues. Tuesday morning another 1,250 refugees arrived in Athens by ferry from three Greek islands.

The junior interior minister for migration, Yiannis Mouzalas, said Athens is desperately trying to negotiate an end to the crisis by exerting pressure at the "European and bilateral level."

bik/jil (Reuters, AFP)