The Welt am Sonntag newspaper, citing "intelligence services," said that the worsening situation in Syria could only drive up the number of refugees. It said that 7.6 million people had been internally displaced inside Syria, with more than 4 million having left the country so far.

The International Organization for Migration (IOM) told Welt am Sonntag that it expected an increase in the number of refugees, rather than any decrease.

Meanwhile, the United Nations refugee agency UNHCR reckoned that more people might make the decision to travel to Europe.

The report came as many parts of Germany, including Bavaria, saw their first snow of the year. The DPA news agency reported that authorities were seeking to make all refugee accommodation suitable for winter, but that there were still shortcomings.

Work to be done

At the Austrian-German border, tents being used to house refugees ahead of their onward journey into Germany were said to be unsuitable at present. However, authorities were set to ensure that tents would be available for new entrants "in the next weeks."

Several German states - including Saxony, North Rhine Westphalia and Brandenburg - have said refugees will be housed in large tents during winter and that these have been equipped with heating and hot water.

Across Europe, the UNHCR and other agencies have been gearing up for the winter, seeking to provide shelter and bedding.

Aid charity Oxfam said it was busy on the Greek island of Lesbos, an arrival point for many entering Europe.

The UNHCR has warned that several countries' restrictions barring refugees from traveling along the West Balkan migration route were putting refugees at risk.

"This is becoming increasingly untenable ... not least in light of falling temperatures and the risk for children and others with specific needs," the UNHCR said on Friday.

The EU warned earlier this month that with winter closing in, a humanitarian catastrophe was looming for tens of thousands of refugees.