Syria presses assault amid fears over mass displacement

Syrian troops pressed an offensive Tuesday on the country's last major rebel enclave where the mass displacement of civilians is sparking fears of a humanitarian catastrophe.

Around 900,000 people have been forced from their homes and shelters in less than three months, leaving huge numbers to sleep rough in the thick of winter.

The United Nations said that half a million among them were children, some of whom have died of exposure in snow-covered camps.

It warned that the crisis could worsen unless a ceasefire is reached.

"Over the past four days alone, some 43,000 newly displaced people have fled western Aleppo where fighting has been particularly fierce," UN spokesman David Swanson told AFP.

A staggering 300,000 people have been displaced since the beginning of February alone, he said.

The wave of displacement is the biggest in nearly nine years of civil war, which has force half of Syria's population to flee their homes.

"The violence in northwest Syria is indiscriminate. Health facilities, schools, residential areas, mosques and markets have been hit," the UN head of humanitarian affairs and emergency relief, Mark Lowcock, said on Monday.

"The biggest humanitarian horror story of the 21st Century will only be avoided if Security Council members, and those with influence, overcome individual interests and put a collective stake in humanity first," Lowcock added.

Russia, the main foreign broker in Syria, has repeatedly vetoed Security Council resolutions on the conflict.

"The only option is a ceasefire," Lowcock said.

Violence on Tuesday left at least two civilians dead, one in a Russian air strike and the other in regime shelling.

Regime backer Iran's state media said a member of its Revolutionary Guards was killed in a rocket strike in Aleppo province.

Save The Children said seven children, including a baby only seven months old, have died from freezing temperatures and bad living conditions in the camps. "We're worried that the death toll will increase given the absolutely inhumane living conditions that women and children are finding themselves in," the charity's Syria director Sonia Khush said.

The UN Office for the Coordination of Humanitarian Affairs said the temperature dipped to minus 7 Celsius in some areas last week.

"Those families who could take some of their belongings as they fled from their homes are reportedly burning whatever they could find, including pieces of furniture and whatever can be spared to stay warm for a short while," it said.

Regime and Russian forces have repeatedly been accused of targeting hospitals and clinics.