BELGRADE, Serbia (AP) -- Blizzards and dangerously low temperatures persisted in parts of Europe on Sunday, prompting Pope Francis to draw attention to the homeless suffering in freezing weather. In Serbia, aid workers scrambled to help hundreds of migrants sleeping rough in parks and makeshift shelters.
The extreme winter weather that has gripped Europe in the past days has caused more than a dozen deaths, left villages cut off, caused power and water outages, frozen rivers and lakes, grounded flights and led to road accidents. Serbia's authorities on Sunday banned river traffic on its stretch of the Danube — one of Europe's main rivers — because of ice and strong wind.
Two men died of cold in Poland on Saturday, bringing the nation's death toll from winter weather to 55 since Nov. 1, authorities said Sunday. Temperatures dropped to minus 30 degrees Celsius (minus 22 Fahrenheit) in the mountains of southern Poland.
In Italy, eight deaths were blamed on the cold, including a man who died in the basement of an unused building in Milan, and another one on a street flanking Florence's Arno River. Francis asked God to "warm our hearts so we'll help" the homeless.
In Belgrade, the capital of Serbia, several hundred men, mostly from Afghanistan and Pakistan, remained in an abandoned customs warehouse by the city's bus station, where aid organizations distributed heaters, blankets, clothes and food in an attempt to keep them warm.
"We are all working together to help these people," Mirjana Milenkovski, a spokeswoman for the U.N. refugee agency, said.
While most of the several thousand migrants in Serbia have stayed in the Balkan country's asylum centers, hundreds have refused to do so, looking for ways to move on toward western Europe.
In neighboring Bulgaria, police said two men from Iraq and a Somali woman died from cold in the mountains near Turkey as they tried to make their way toward Europe. Many in the Belgrade warehouse were sick after few days in extreme cold, aid workers said.
"The next few days are critical, and for sure the health condition of these people is worsening," said Stephane Moissaing, MSF Head of Mission in Serbia.
German federal police said Sunday they picked up 19 migrants — including five children — at a highway stop in Bavaria who were suffering from hypothermia after their driver disappeared and left them on the back of an unheated a truck for hours in the freezing cold.
Elsewhere, emergency measures were declared in several municipalities in Serbia's south and southwest. Dozens of villages in Serbia's remote Pestar region were sealed off by heavy snow, prompting the evacuation of some 100 people by emergency crews. Authorities said 70 kilometers of water pipes there were frozen.
Numerous villages in northern Bulgaria also were left without electricity and water. Power outages were also reported throughout the region.
Polar temperatures of between minus 15 and minus 26 degrees Celsius (5 and minus 15 Fahrenheit) saw ice forming on the Adriatic sea and the Danube, while countless smaller rivers, lakes and ponds froze.
Montenegro's port of Bar in southern Adriatic closed down on Saturday, while sea traffic was suspended for days in neighboring Croatia.
Police in Bulgaria said a passenger train was derailed Sunday after it hit a pile of snow in the central part of the country. Snow fell on Istanbul, Turkey, for the third straight day, and Turkish Airlines grounded hundreds of flights in and out of the city's two airports.
A dozen major roads remained closed in Romania due to heavy snow and some ferry services between Romania and Bulgaria across the Danube were canceled. Authorities said schools would be closed Monday and Tuesday in many areas, including in the capital, Bucharest.
Four Portuguese nationals were killed when a bus skidded on an icy road in eastern France early Sunday. The road is notorious for fatal accidents.
Black ice across northern and western Germany has caused countless accidents and injuries — firefighters in the city of Hamburg said Sunday they were called to weather-related accidents 415 times during the weekend.
Near Hannover, one person died in a car accident when his car skidded against a tree on an icy road, German news agency dpa reported. City authorities shut down the public transportation system and across the country, people were asked to wait out the severe weather conditions at home.
For hundreds of Muscovites, however, the fact that the temperature had plunged to minus-27 Celsius (minus 17 Fahrenheit) was no reason to avoid going for a group bicycle ride. About 500 cyclists, many equipped with fur hats and other nonstandard gear, held a ride of about eight kilometers (five miles) along the Moscow River on Sunday as the capital shivered through a fierce cold snap.