Migrants and refugees stand in line in freezing temperatures to receive food as they wait to cross the border from Greece to Macedonia near Idomeni on Jan. 21. (Sakis Mitrolidis/AFP/Getty Images)

The back door to Europe may be closing.

A historic wave of migrants fleeing war and poverty crossed into Western Europe last year from the Middle East and beyond, with most taking a precarious route via Greece then onward through the Balkans. While the onset of winter has slowed the tide of newcomers, more than 2,000 a day are still arriving.

Yet from the Greece-Macedonia border to Austria and Germany and northward to Denmark and Sweden, a domino effect is taking shape as nations in Europe suddenly move to keep more migrants out. It happens as Europe’s plan to manage a humanitarian crisis remains in disarray and a surge of new migrants is expected as soon as March.

Increasingly, nations are taking matters into their own hands, putting up policies aimed at cutting the migrant flow and weeding out all but those most at risk from war. This is taking place amid rising security fears in Europe after the terrorist attacks in Paris by assailants that included militants who disguised themselves as migrants, as well as hundreds of sexual assaults in Cologne, Germany, on New Year’s Eve in which asylum seekers are among the suspects.

“We are in a period of unprecedented anti-migrant, anti-foreign sentiment, in which everybody sort of retreats in their own circle and says, ‘No one can come in,’ ” said William Lacy Swing, director general of the International Organization for Migration.

Advocates of stricter controls insist national steps are the only way to curb new arrivals in the face of Europe’s failure to manage the crisis. Countries across the region have said that many of the migrants who arrived last year — as well as many of those coming now — are not genuine asylum seekers and have no legal right to stay.

[Along the migrant trail, pressure grows to close Europe’s open borders]

Now, countries are taking steps unilaterally to prevent migrants from arriving. Alarmed by the vast numbers of arrivals, Sweden and Denmark imposed fresh controls this month on what were once open borders. In an effort to reduce the number of arriving migrants, Sweden — the nation that last year received more asylum seekers per capita than any other in Europe — is barring entry to travelers entering without proper documents.

On Tuesday, Macedonia — the key entry point for migrants leaving Greece and traveling to the rest of the European Union — shut down its southern border. That move came after a decision in November to grant transit only to Syrians, Afghans and Iraqis. Macedonia briefly reopened its border Thursday, but it limited passage to a few hundred nationals from those three war-torn nations who also pledged to seek asylum only in Austria or Germany.

The border was quickly closed again, however, amid fears that Macedonia might soon begin allowing only families and women to pass. Mersiha Smailovic, spokeswoman for the pro-refugee group Legis, based in Skopje, said Macedonian authorities told her organization Thursday that “single men” would not be allowed in — a policy she said would force thousands of male asylum seekers to hire smugglers or would leave them stranded in Greece.

“This is against the Geneva [Conventions] and Macedonian law,” she said. “We might see concentration camps [in Greece] with only single young men, like in the Bosnian War or World War II.”

On Thursday, aid workers said that Greek officials on the Macedonian border were canvassing thousands of waiting migrants about their destinations and nationalities. Officials from Doctors Without Borders warned that the new restrictive policies could lead to a repeat of last spring’s humanitarian crisis, before Macedonia began granting migrants temporary transit visas.

A record number of migrants and refugees are attempting perilous journeys to find a safer, better life in Europe. Here's why they're leaving and how they're being received. (Jason Aldag and Gillian Brockell/The Washington Post)

“People are confused,” said Gemma Gillie, who is working with Doctors Without Borders on the Greece-Macedonia border. “There is definitely a tense atmosphere because some people, including many children, have now been waiting for days. . . . It is a strange mix of fear and exhaustion. It is very cold.”

[German chancellor pledges crackdown on criminal asylum seekers]

Still, migrants continue to attempt the crossing from Turkey — a journey made more perilous in the winter by frigid Aegean waters. On Friday, at least 45 people, including 17 children, drowned after two boats capsized near Greek islands, rescue officials said.

Indefinite controls

Stricter guidelines have also been instituted in Germany, the nation whose open-door policy made it by far the single largest destination for migrants last year. German authorities are still letting in thousands of migrants each week, but they have begun blocking a number in the low three figures each day. They are refusing entry, for instance, to anyone who wants to claim asylum in European countries farther north or those who admit to fleeing their homelands for economic reasons.

At the same time, Chancellor Angela Merkel, the architect of Germany’s open-door policy, is under increasing pressure to do an about-face. On Tuesday, 44 lawmakers from her center-right coalition demanded she take further steps to curb new entries. It happened as critics said that any country that did not take such steps would be the one left with unwanted migrants on its doorstep.

“One country after the other is turning away from the open-border policy,” said Stephan Mayer, a national lawmaker from the Christian Social Union, Merkel’s coalition partner. “Germany also needs to change directions as quickly as possible when it comes to its refugee policy.”

On Thursday, German Interior Minister Thomas de Maizière said special controls on the Austrian border — initially meant to be temporary — would remain in place indefinitely.

“We will send back people who do not have valid entry documents and do not apply for asylum in Germany,” de Maizière told German radio.

Neighboring Austria, meanwhile, is in the midst of an even tougher crackdown. Starting Friday, Vienna says it will block migrants who are not seeking to make immediate asylum claims in either Austria or Germany.

Interior Ministry spokesman Karl-Heinz Grundböck said that Austria would not base its decisions on migrants’ nationalities. But Austrian police officials said they have standing orders to allow only Syrians, Afghans and Iraqis to travel through Austrian territory. Migrants from other nations would need to apply for immediate asylum in Austria or they will be forced to go back to Slovenia.

This week, Austria is set to complete a 2.3-mile fence at a key migrant entry point on its border with Slovenia. Austrian officials on Wednesday also announced new caps on asylum seekers, but they characterized these more as “guidelines” than as firm figures.

[The big thing missing from Europe’s solution to the refugee crisis? Refugees.]

Failing scheme

The measures come at a time when Europe is trying, and failing, to create a working system to manage the migrant crisis, with leaders scrambling for a solution ahead of a planned summit in February and before an expected surge in arrivals this spring.

Facing opposition from a bevy of nations, Europe’s scheme to legally bring in migrants thus far has failed. Out of an intended total of 160,000 asylum seekers, the European Union has legally relocated 331. E.U. officials are still pressing for a system that compels even nations highly resistant to migrants — including Hungary and Poland — to accept them.

At the same time, a plan to create new “hot spot” zones, or large processing centers, in entry nations Greece and Italy is behind schedule and plagued by political infighting. Greece and Italy have balked at the notion that asylum seekers might need to wait out application processing within their territories.

“We have six to eight weeks” to solve the problem, Dutch Prime Minister Mark Rutte told a panel in Davos, Switzerland, on Thursday.

Stephanie Kirchner in Berlin and Elinda Labropoulou in Athens contributed to this report.

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