Slovenia has called in the army to help it manage a flood of refugees seeking to reach northern Europe ahead of winter, as the small EU state becomes the latest trouble spot on the migrant trail.
With at least 9000 people landing on Europe's beaches every day, there appeared to be no end in sight to the continent's biggest migration wave since World War II.
But a vaunted European Union scheme for relocating 160,000 asylum seekers around the bloc has made no progress, an EU source said.
Since Saturday, when Hungary sealed off its border with Croatia, more than 19,460 migrants have arrived in Slovenia, with the nation of two million people warning it is struggling to cope.
"The inflow of migrants over the last three days has exceeded all manageable possibilities," the Slovenian government said on Tuesday (local time).
"The last 24 hours have been the toughest and most demanding since the start of the crisis," it said, warning it was "delusional" to expect small countries to succeed where larger ones had failed.
Parliament will be asked to approve legislation allowing soldiers to intervene in the crisis "under very specific circumstances", the government said.
Under current law, the army can only provide technical and logistical support.
However, "this does not mean a state of emergency", Prime Minister Miro Cerar told journalists.
In Greece, the crisis showed no sign of abating with a clear "spike in arrivals" that left 27,500 people packed on the Greek islands by Tuesday morning, the UN said.
Last month, the EU announced plans to relocate 120,000 asylum seekers from overstretched frontline states Italy and Greece by means of a compulsory quota system that was fiercely opposed by some eastern members of the bloc.
The plan requires most of the 28 member states to accept a share of 160,000 people from the two Mediterranean nations over two years.
But an EU source said the scheme has barely got off the ground.
So far only 19 Eritrean asylum seekers have been relocated from Italy to Sweden although another 100 people are due to be flown to other cities in the coming days.
Member states have also been slow to follow up with promised financial help - out of the 2.8 billion euros (AU$4.37 billion) pledged at an emergency EU summit on September 23, only about 474 million euros has materialised.
Meanwhile on the ground, thousands were left stranded in wet, freezing weather on Croatia's frontier with Serbia, after travelling up through Greece and Macedonia.
Around 1000 were waiting to cross into Croatia at the Berkasovo checkpoint after spending the night in the cold, with dozens of tents pitched along the roadside which was turned into a muddy swamp after hours of heavy rain.
"Open! Open!" chanted the crowd as border guards limited the flow to only 50 people in every half hour.
"It is so cold. We couldn't sleep. I came 24 hours ago and spent the night in a tent," said Syrian Azme Solei who said he had spent a year living in a refugee camp in Turkey but decided to leave because of the "unbearable" living conditions.