Thousands of weary migrants and refugees continue to march across the Balkans towards western Europe. However, thousands have become stranded in worsening autumn weather after Hungary sealed its borders with Serbia and Croatia, triggering a chain reaction in other overwhelmed states.

In Slovenia, mounted riot police led a column of people stretching as far as the eye could see as authorities cautiously lowered barriers and intensified efforts to cope with a human tide unseen in Europe since the Second World War. Slovenia has deployed military units to support police on their overwhelmed southern border with Croatia. With far too few buses available in Slovenia to cope, most people walked 15km (9m) on rural lanes past cornfields and pastures to reach a refugee camp.

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Refugees and migrants make their way on foot towards Brezice, SloveniaSrdjan Zivulovic/Reuters
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Two local women observe new arrivals walking in Brezice, SloveniaSrdjan Zivulovic/Reuters
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A mounted policeman leads a group of migrants and refugees near Dobova, SloveniaSrdjan Zivulovic/Reuters

A fire broke out at a camp in Brezice, on Slovenia's border with Croatia. The cause is not clear, but people had been lighting fires outside their tents to ward off the chilly weather. Ivan Molan, the mayor of the town has said the town is full and cannot take any more refugees or camps.

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A policeman and migrants stand between tents after a fire swept through a camp in Brezice, SloveniaAntonio Bronic/Reuters

Dozens of migrants and refugees, including women and small children, crossed a river in the cold of the night while crossing from Croatia to Slovenia. More than a thousand people were dropped at the border by train from Croatia and directed to cross the frontier on foot. Threading through an unknown area, some found themselves by the Sutla river. With the temperatures below or around zero degrees Celsius (32F), they waded through the river or swam over, carrying their children and belongings. Then they climbed up the muddy river banks to be escorted on by Slovenian police.

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A man wears a plastic rain poncho as he waits at the Bregana-Obrezje border crossing between Croatia and SloveniaAFP
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Migrants and refugees disembark from a train in Kljuc Brdovecki, Croatia, on their way to the Slovenian borderAFP
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People wait in the rain at the Trnovec border between Croatia and SloveniaJeff J Mitchell/Getty Images
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Migrants and refugees cross the Croatia-Slovenia border in TrnovecAFP
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Slovenian police help people stuck in cold and wet weather in Trnovec at the border with CroatiaJeff J Mitchell/Getty Images

On Slovenia's frontiers with Croatia and Austria, aid workers toiled to erect enough tents and other emergency accommodation to shelter up to 14,000 travellers, more than five times the tiny nation's previous official limit. Tensions flared on Slovenia's border with Austria as police in both countries struggled to keep migrants walking in orderly queues to buses bound for Austrian refugee centres. At one point, a few hundred people being confined by Slovene police broke free and ran across the border — seeking to get in front of others waiting hours for buses. Slovene officers' bursts of pepper spray failed to stop them, but Austrian police erected physical barriers that blocked the interlopers' path to buses. They eventually were persuaded to walk back to the end of the line.

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A man talks to Slovenian police officers at the exit of a makeshift camp near the Austrian border in Sentilj, SloveniaLeonhard Foeger/Reuters
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People hold on to a child as migrants and refugees attempt to break through a cordon in front of a makeshift camp in Sentilj, Slovenia, near the Austrian borderLeonhard Foeger/Reuters
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Members of the Austrian army guard a group of people waiting for transport in Spielfeld, on the border with SloveniaLeonhard Foeger/Reuters
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A child with red eyes is seen after Slovenian police officers used pepper spray as a crowd of people attempted to break through a cordon in front of a makeshift camp near the Austrian border in SentiljLeonhard Foeger/Reuters
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People walk towards the Austrian border after arriving by train in the village of Sentilj, SloveniaLeonhard Foeger/Reuters

Interior secretary of state Bostjan Sefic said Slovenia, an Alpine land of barely two million people, needed much more help immediately from bigger European Union (EU) partners to cope or the country might have to adopt border-toughening measures. "If this continues we will have extreme problems. Slovenia is already in dire straits, an impossible situation," Sefic said as politicians debated whether to increase the military's powers to manage border security.

Hundreds of migrants and refugees pushed their way into Croatia after spending the night out in the open in freezing cold, waiting to cross from Serbia into the EU. Exhausted and chilled, people started walking down the muddy border passage and over the corn fields. Croatian police had been deployed on the boundary to stop them but then moved away. UN refugee agency officer Francesca Bonelli said around 3,000 people were there overnight, including little children, the elderly, people in wheelchairs and many sick and exhausted.

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Migrants and refugees stand in the mud as they wait in a field in the village of Berkasovo in Serbia near the border with CroatiaJeff J Mitchell/Getty Images
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An elderly man wrapped in a blanket rests on a cane near the border between Serbia and CroatiaJeff J Mitchell/Getty Images
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Refugees and migrants walk through a field of muddy blankets near the border crossing between Serbia and CroatiaJeff J Mitchell/Getty Images
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A woman carries her child along a dirt road near the Serbian village of Miratovac after crossing the Macedonian borderArmend Nimani/AFP
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People cook corn and warm up by a fire in Bapska, Croatia, after crossing the border from SerbiaDado Ruvic/Reuters
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Children pose after crossing the border from Serbia in Bapska, CroatiaDado Ruvic/Reuters
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A child stands with other new arrivals in Tovarnik, Croatia, near the Serbian borderDado Ruvic/Reuters
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Children look out from a tent at a migrant camp in Opatovac in Croatia, just over the border from SerbiaDado Ruvic/Reuters
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A Syrian woman waits to cross the border into Croatia near the village of Berkasovo, SerbiaMarko Djurica/Reuters
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Migrants and refugees carry their belongings as they walk through a field near the village of Berkasovo, Serbia, towards the border with CroatiaMarko Djurica/Reuters
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Migrants near the village of Berkasovo in Serbia wait to cross the border into CroatiaJeff J Mitchell/Getty Images

Croatia, which has erected relatively few shelters along its borders with Serbia and Slovenia, directed thousands into special trains and bus convoys to Slovenia in an apparently concerted effort to clear a backlog built up since Saturday 17 October, when Hungary closed its borders with Croatia.

Hungary, long the most popular eastern gateway for people fleeing conflict and poverty in the Middle East, Asia and Africa, has closed its borders to migrants progressively over the past month, forcing the tide west through Croatia and Slovenia. All three nations have expressed fears of ending up stuck accommodating tens of thousands of asylum seekers indefinitely if other EU nations farther north close their borders too.

More than half a million refugees and migrants have arrived by sea in Greece this year and the rate of arrivals is rising in a rush to beat the onset of freezing winter, the United Nations said.

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Syrian refugees bail out their sinking dinghy and call for help off the Greek island of LesbosYannis Behrakis/Reuters
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People embrace each other upon arriving at a beach on the Greek island of Lesbos after crossing a part of the Aegean Sea from the Turkish coast on an overcrowded raftYannis Behrakis/Reuters
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Refugees and migrants arrive at the port of Piraeus, near Athens aboard the passenger ferry Blue Star Patmos from the island of LesbosAlkis Konstantinidis/Reuters
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A young Syrian refugee carries his disabled relative at the port of Piraeus as they walk with other migrants and refugees to find transportation to central Athens or continue towards the Greek-Macedonian borderLouisa Gouliamaki/AFP

The refugees' primary goal is to reach Germany or Scandinavian nations, which traditionally have offered strong supports for asylum seekers.