At least 18 people have died in Ukraine and 10 in Poland after heavy snow fall and a sudden drop in temperatures across east Europe.
Three deaths were also reported in Serbia and one in Bulgaria.
Ukrainian officials said nearly 500 people had sought treatment for frostbite and hypothermia in just three days.
And over that time, more than 17,000 people had sought refuge in some 1,500 shelters, Ukrainian media reported.
Temperatures have plunged to -16C (3F) during the day and -23C (-10F) at night, the Associated Press reports.
Twelve of the dead were homeless people, whose bodies were discovered on the streets, Ukraine's Emergency Situations Ministry said.
Poland had been having a relatively mild winter, until temperatures dropped last Friday from just below freezing to -26C (-15F).
Malgorzata Wozniak of Poland's interior ministry told the AP that elderly people and the homeless were among the dead.
Polish forecasters have warned that temperatures could fall further during the week, to below -20C during the day and -30C at night.
In Serbia, police reported that the snowy conditions had led to the deaths of a woman and two elderly men. Two other men, in their 70s, are believed to be missing in the south of the country.
The freezing conditions also claimed a life in neighbouring Bulgaria.
Emergency shelters offering food and heat are being set up in the Bulgarian capital Sofia and the Czech capital Prague, according to AP.