Most nations along Europe's refugee corridor shut their borders yesterday to those not coming from war-torn countries such as Syria, Afghanistan or Iraq, leaving thousands of others seeking a better life in the continent stranded at Balkan border crossings.
The overnight decision triggered the domino effect that both asylum-seekers and European nations had feared given the record number of people fleeing to Europe this year, and new fears after the deadly Paris attacks of possible militants coming in with refugees.
Macedonia, Serbia, Croatia and Slovenia weren't allowing in the so-called economic migrants whose countries aren't shattered by armed struggles or wars.
In the Greek village of Idomeni at the border with Macedonia, police said the border has essentially been shut down to all since yesterday morning. Some 3,000 people are waiting at a camp nearby that provides temporary shelter for those heading north through the Balkans.
About 500 people from Iran, Morocco and Algeria gathered on the border line between Greece and Macedonia to protest the closure. As a result, nobody else from the nationalities that Macedonia is letting through - Syrians, Afghans and Iraqis - were able to cross.
Dariush Yazdani (25), from Tehran, said he was determined to reach Germany, and faced imprisonment were he to return to Iran. "I will never go back," he said.
Mohammed Mirzam (30), from Afghanistan, knows he will be let through, but his wife and two children, Ilia (5) and Elena (3) are Iranian nationals and will not.
"We're trapped," he said, from the Greek side of the border, at Idomeni. "They won't let my family across. We have no money, and we're waiting without any idea of what is to happen."
On the Serbian border with Macedonia, the Serbs were letting in only migrants from Syria, Afghanistan and Iraq. And on the Croatia-Serbia border, the Croats were accepting people only from those three countries plus Palestine.
Slovenia - the next country in the chain - also said it has been turning back the so-called economic migrants.
"This is going to be definitely a challenging situation," said UN refugee agency spokeswoman in Serbia, Melita Sunjic.
"UNHCR does not think that there is any nation that can be excluded from international protection based on their nationalities, but each case individually should be screened based on the merits of the case."
The partial closure of the borders could trigger huge build-ups of desperate people along the Balkan corridor that has seen hundreds of thousands of people cross as they head to wealthy EU states, mostly Germany. Although Syrians are the biggest group among the asylum-seekers, tens of thousands of people fleeing poverty - such as Pakistanis, Bangladeshis or Sri Lankans - have also joined the surge.
Meanwhile, the US House of Representatives voted to temporarily block refugees from Syria and Iraq from entering the US, though it's not clear whether President Obama will be able to veto the legislation.
The Republican bill, which passed 289-137 with the help of some Democrats, would block Syrian and Iraqi refugees from entering the US unless four top US law-enforcement and national security officials affirm to Congress that each individual isn't a security threat.
Senate Minority Leader Harry Reid said Obama isn't likely to have to veto the House bill. "No way will it get passed," said Reid, suggesting the measure won't have enough support in the Senate to advance to the president's desk.