Slovenia has warned it may be forced to slow the influx of refugees arriving from Croatia and Serbia. Migrants taking the Balkan route have moved on to Slovenia after Hungary's right-wing government closed its borders.
The Slovenian government has said it will only take in a maximum of 2,500 migrants a day, following Hungary's decision to close its border with Croatia on Saturday.
On Sunday, Slovenia refused to allow in a train carrying 1,800 migrants from Croatia, after more than 3,000 people surged into the tiny EU member state the day before.
Tension is building among thousands of migrants as they remain stranded in fog and cold weather in their quest to reach a better life in Western Europe.
Slovenian officials have said they can't accept 5,000 migrants per day as asked by Croatia, which is likely to cause further bottlenecks.
"If we would accept 5,000 migrants per day that would mean 35,000 would be in Slovenia in 10 days," said Interior Ministry official Bostjan Sefic, taking into account those who leave for Austria. "That would be unacceptable."
Meanwhile, the United Nations refugee agency warned that Hungary's decision to close its border for migrants has increased unnecessary suffering for migrants using the Balkan land route to reach Europe.
"The decision by Hungary to close its border has certainly added to the suffering and misery and the length of the journey for these desperate people," said Babar Baloch, regional spokesman for Central Europe for the UN High Commissioner for Refugees. "There will be challenges if the process becomes slow or we have a backlog of people."
The bottlenecking due to Hungary is the latest demonstration of EU's uncoordinated response to the surge of people reaching its borders.
More than 600,000 people, mostly Syrians, have reached Europe since the beginning of the year.
Hungary criticized for border closures
Hungary has said it decided to close the border with Croatia on Saturday after EU leaders last week failed to agree on a plan backed by Hungary to send EU forces to block migrants from reaching Greece from Turkey. It did the same on September 15 on the border with Serbia after erecting a razor wire fence - guarded by military troops - on both frontiers.
Slovenia now fears that if Croatia continues taking more migrants than it is able to send forward, there could be a "spillover" of migrants.
"The army's assistance does not mean there is an extraordinary situation in Slovenia, but that the government wants to manage the situation at the border," said Slovenian Prime Minister Miro Cerar on Saturday, after his country deployed its army to help assist border police with "logistics and equipment."
Some 300 kilometers (185 miles) to the southeast of Ljubljana, about 2,000 migrants were queuing on the Serbian border with Croatia.
Hundreds of people, some in jackets or blankets handed out by volunteers, were sitting on pieces of cardboard on the ground as they waited.
"We've been here since 7 a.m. this morning and I am dead tired after 48 hours in buses," 23-year-old Rawan from Damascus told the AFP news agency as she helped volunteers from the Czech Republic to explain to refugees what was happening.
Once refugees enter Croatia, the migrants are transported by bus to a refugee center in the village of Opatovac. From there they are either taken to a train station or put on to buses for Slovenia.
"Everything has slowed down since Hungary closed the border," a police officer at the Berkasovo border crossing in Serbia told AFP.
jar/cmk (AP, AFP)