Migrants cross a railway on their way to the Austrian – Hungarian border near Hegyeshalom, Hungary, on Monday Sept. 28, 2015. (AP Photo/Christian Bruna)

BAPSKA, Croatia (AP) — Doctors treated children including newborns for exposure as dropping temperatures Monday worsened the plight of asylum-seekers walking for days in hopes of reaching sanctuary in Europe.

A new group of migrants crossed into Croatia late Sunday, crossing the border near the small village of Bapska. They walked through cornfields and forests to pass through a small gate that marks the border between Croatia and Serbia.

Vladimir Bozic, a physician from Doctors without Borders, said he had treated many young children.

“We saw a 1-month old baby, even (one who was) 15 days,” Bozic said.

Volunteers from the U.N. High Commissioner from Refugees handed out blankets, warm drinks and food to the people, who are fleeing conflict and poverty in the Middle East, Africa and Asia. They walked in the rain, through muddy fields, and are suffering in rising numbers from colds and the flu after days or weeks on the move.

“I expect even more with worsening of these cold conditions,” Bozic said. “Winter is coming.”

Migrants lined up at the Opatovac transit center to take trains out the country. About 78,000 asylum seekers have crossed into Croatia since Sept. 15, when Hungary closed its border with Serbia.

That decision triggered a chain reaction in the wave of migrants trying to get to the richer countries of Europe, with the surge being forced to go through Croatia rather than going directly to Hungary.

Saed Al Mousawi, who fled from Afghanistan, said that the drop in temperatures had made many feel unwell, especially the children. The route has been hard, but he’s determined to keep going.

“We have dreams to have a peaceful life, without war, without any other distractions,” he said. “We want to just live in a peaceful atmosphere.”