The toll from Europe's killer cold snap hit at least 360 on Monday with nine new victims found in Poland, most of them homeless, and five drowned when a Bulgarian dam burst after torrential rain.

The rain and snowstorms lashing southern Bulgaria collapsed the dam early Monday, submerging the small village of Biser under 2.5 metres (eight feet) of water, emergency services said.

Biser mayor Zlatka Valkova told state news agency BTA three elderly men had drowned in their homes and a massive rescue effort was under way in the village of about 800 people. National radio reported two other people were killed when their car was swept off a bridge.

"People are in panic," regional mayor Mihail Liskov said on national radio. "Ninety percent of the village is under water."

Two larger dams in southern Bulgaria risked spilling over and residents were told to prepare to evacuate. Heavy rains also triggered a landslide that derailed a train near the Turkish border. No injuries were reported.

Meanwhile, temperatures in Poland plunged to as low as minus 24 degrees Celsius (minus 11 Fahrenheit), bringing another deadly night for the homeless.

As has been the case throughout the 10-day-old cold snap, transients have borne the brunt of the suffering, with frozen victims found in abandoned and unheated homes, fire escapes or makeshift shelters on Europe's streets.

In a bid to save lives, Poland's homeless shelters have dropped a ban on drunken individuals.

Monika Golebiewska, a Warsaw police officer whose beat is a daily patrol bringing food and clothing to the homeless in the city's hardscrabble Praga district, said she has been unrelentingly busy since the cold snap started.

"New (fatal) cases are reported to us daily. Just today we got calls telling us about two new ones, one of someone who was living in a tent and another of someone in an abandoned train station," Golebiewska said. "I've got more and more people to feed, but just 40 portions of soup a day."

Overall, 107 people have died of hypothermia in Poland since winter hit in November. The current cold snap began at the end of January and across the continent, authorities have reported at least 360 weather-related deaths.

In neighbouring Lithuania, where the mercury has dipped to minus 31 Celsius (minus 24 Fahrenheit), the deaths of 12 more people over the weekend brought the cold snap's toll to 23.

Hungarian authorities have reported at least 12 dead since the onset of the cold.

Italian authorities continued to clear up after a rare snow storm blanketed Rome over the weekend and crews struggled to restore power to about 60,000 homes across the country, especially in the Tuscan cities of Siena and Arezzo.

Italian energy giant ENI warned earned it may have to cut gas supplied to customers after shortfalls in gas imports from Russia.

Elsewhere across Europe, authorities struggled to clear clogged roads and runways that left tens of thousands of travellers stranded over the weekend.

After cancelling half its flights Sunday, operators of London's Heathrow Airport, the world's busiest passenger hub, said its schedule was almost back to normal Monday.

While parts of Britain were beginning to warm above freezing, other European nations remained in an icy grip.

In the Czech town of Kvilda, near the Czech-German border, the temperature hit minus 39.4 Celsius (minus 38.92 Fahrenheit), the lowest recorded in the country this winter.

Switzerland also recorded year lows, dropping to minus 35.1 Celsius (minus 31 Fahrenheit) in the eastern Graubuenden canton on Sunday night.

The bitter cold has engulfed most of Europe and even crossed the Mediterranean into north Africa, where as many as 16 people were killed on Algeria's snow-slicked roads or in other weather-related accidents.

Rare snow also fell in southern Tunisia for the first timme in some 40 years, media reported, with temperatures well below freezing in some areas of the country and villages cut off.

In France, 39 of the country's 101 regions were on alert for deep cold or snow, down from more than half the regions at the weekend, as a new record for electricity consumption was predicted later Monday.

Five people have died in weather-related incidents since the cold snap hit France, the latest a 56-year-old homeless man who is believed to have succumbed to hypothermia in a suburb of Paris.

People in the Netherlands, however, were sharpening their skates in the hope that a legendary long-distance race on frozen canals may be held for the first time in 15 years, though organisers cautioned Monday the ice was still too thin.

burs/wat/mb