At the migrant and refugee registration center in Presevo, Serbia, a small girl wearing a pink coat screams with delight as her older sister bends down and allows her to pet a stray cat she had been carrying in her arms.
It is around noon and the little girl's high-pitched squeals condense to form tiny white clouds in the -4 degrees Celsius air. Snow covers the ground; others sit around, shivering from the bitter winds.
According to forecasters, nighttime temperatures in the area could plummet to around -10 degrees Celsius over the next two weeks, and aid workers are worried the prolonged cold spell could have deadly consequences, especially for children.
"The winter conditions are our main concern now," said Astrid Castelein, head of the UNHCR office in Presevo.
Earlier this week, Save the Children reported several possible cases of hypothermia and frostbite among those traveling, while UNICEF released a statement describing many youngsters arriving in the Balkans as "physically exhausted, scared, distressed and often in need of medical assistance."
Roughly 1,000 migrants and refugees — from Syria, Afghanistan and Iraq — continue to arrive in Presevo daily. To get there, they first travel through Macedonia, usually by bus or train, but are forced to walk about two kilometers at the border with Serbia. Once they reach the Serbian town of Miratovac, they can take a free shuttle to Presevo.
Urgency adds dangers
Inside the registration compound, a sense of urgency is palpable, not just to get out of the freezing air, but to get out of Serbia altogether.
But this drive to carry on quickly causes extra complications, Castelein said.
"An Afghan woman's child was diagnosed with pneumonia so she was brought to the hospital," she explained, "but she absolutely wanted to continue her travel and was about to leave even though the doctors were not in favor of discharging the child. The cold outside would make it even worse. Refugees don't want to take the time to recover here."
The reason: They fear the borders of Western Europe could close at any moment.
It is a fear Christina, 19, and David Bshara, 17, understand. The siblings left Damascus two weeks ago to reach their mother, who now lives near Hanover, Germany.
They decided to leave in winter, "because Turkey said it would make a visa (required) for Syrian people," David said. He also described how his father and little sister had to remain in Syria because the family did not have enough money for everyone to travel.
"It's too hard," Christina said, when asked about her remaining family in Damascus. "You can't do anything — just stay at home, eat, sleep … there's no real life."
‘No end in sight’
Turkey did impose visa requirements on Syrians arriving by air and sea from third countries shortly after the Bsharas began their journey. Despite Ankara's efforts to stem the flow of refugees into Europe, many experts believe 2016 could see a similar exodus to last year's.
"When we started our work, we thought the situation would only last one or two weeks," said Valon Arifi in a smoky café across the street from the registration compound's main entrance.
He's the leader of Youth for Refugees, a local group that works around the clock to provide migrants and refugees with everything from winter clothes to travel fare.
"Now there's no end in sight,” he said. “I think in spring the number will go up again. I think one million more will come to Europe. … And I think this will be a problem more than people think."
Arifi's concerns are echoed by many.
On Wednesday, Serbia announced it would begin limiting migrant passage to those wishing to seek asylum in Austria or Germany. The decision came after Austria said it would cap the number of people allowed to claim asylum inside the country this year at less than half of last year's amount.
Experts said the new rules could easily cause a backup of people and stricter controls farther down the migrant route. But it is a situation Serbia has been preparing for.
VOA has learned that the Serbian government has identified a number of former factories, hotels and buildings throughout the country that could be renovated and used to host migrants and refugees who get stranded.
The UNHCR — the United Nations refugee agency — has pointed out that these people always have the right to seek asylum in Serbia. However, the thought of remaining in the country does not appeal to most passing through Presevo.
"Serbia? No, no, no," said Fawaz, 25, from Damascus who is traveling alone. "I don't think I could stay in Serbia. It's too difficult."
"I don't want to come to Europe at all," he confessed, "I have no friends, no one. But what can I do? I can't go to the Gulf countries. I can't go to Turkey. It's stay in Syria and die, or go to Europe—you have no choice."