More than 11,000 children living in camps in northern Syria have been affected by torrential rains that have caused floods and washed away tents.
Severe winter weather has caused misery in Idlib province, which is home to around 1.5 million Syrians who have been displaced from other parts of the country.
Save the Children said on Thursday that reports of illnesses among children there are increasing, but many are unable to get to medics because of the flooding.
“The conditions in the camps and settlements where displaced children are living are miserable, with families suffering through freezing temperatures with only the most basic protection from the elements,” said Save the Children’s Syria response director, Sonia Khush.
“We urgently need to scale up life-saving support for children and families facing a harsh winter in Idlib and elsewhere in Syria,” she added.
The unusually bad weather comes at a time when violence in the beleaguered province is rising, as rival rebel groups battle for control.
The fighting has made it difficult for aid groups to respond to the crisis.
Idlib is home to one of the densest concentrations of displaced people in the world, and another major offensive there could send another 700,000 fleeing for a second time.
Storms have also caused havoc for Syrian refugees in Lebanon.
Tens of thousands have been hit by strong winds, rain and heavy snowfall, and hundreds had to be evacuated after their shelters were flooded.
