The death toll is rising in Europe where bitterly cold air has slammed much of the continent, bringing high winds and heavy snowfall.

Poland Tuesday reported another six deaths due to freezing temperatures, while officials across central and eastern Europe say hundreds of villages – and tens of thousands of people – have been cut off from supplies as snow continues to pile up. Ice has also been a problem, clogging rivers and shutting down key ports.

Serbian officials said Tuesday they were planning to deploy army explosives experts to break up the ice blocking parts of the Danube and Ibar rivers, fearing the ice could cause flooding.

The extreme cold has been blamed for almost 400 deaths across Europe. In Ukraine, where temperatures have fallen below minus 30 degrees Celsius, the cold is blamed for at least 122 deaths. Many of the victims were homeless.

Even the prospect of warmer temperatures has officials worried.

Bulgaria Tuesday declared a day of mourning after melting snow caused a dam near the village of Biser to collapse, killing eight people. Officials and witnesses describe a wall of water sweeping through the main street, washing away homes and cars.

After visiting the destruction, European Commissioner for Crisis Response Kristalina Georgieva said she feared, “the worst is yet to come.”

“Two weeks with freezing temperatures will be followed by a sharp warm spell. The snow will be melting and we have to help those who suffered and use the next weeks to prevent further damage.''

Compounding the problem has been a shortage of natural gas.

Russia's gas export monopoly Gazprom blamed the cold weather for extremely high demand, saying it had been unable to satisfy gas shortages in at least eight European nations, ranging from Italy to Poland. Russian and Gazprom officials said Tuesday the flow of gas has started to return to normal.

Despite the high death toll, and reports of heavy snow in areas unaccustomed to such extreme cold, the World Meteorological Organization said the weather system had yet to set any new records.

The WMO says, in contrast to Europe, much of North America has so far seen an usually warm winter.