The number of Afghans, particularly children, killed in severe winter weather could be much higher than official estimates, an aid agency says.
Afghanistan is facing its worst winter in more than a decade
The Catholic Relief Services says up to 1,000 children may have died because of the intense cold and lack of food.
Afghan officials said earlier this week that more than 260 people have perished, many of them children under the age of five.
Afghanistan is facing its worst winter in more than a decade.
The Catholic Relief Services said that survey teams sent to 16 villages in a single district in Ghor province found an average of five deaths of children under five years of age in each village.
Most of the 250 villages in Shahrak district and two other districts could not be reached by the team because of the heavy snow, the agency said.
"I'd say several hundred, and perhaps more, children have died, and perhaps more children will die if they cannot get access to medicines and other relief supplies," Paul Hicks of the Catholic Relief Services told Reuters.
"Our fear is that more than 1,000 deaths could be a conservative estimate."
The deputy provincial governor of Ghor province, Ikramuddin Rezaie, said the government had recorded 35 deaths of children in Shahrak in the past three days.
He said the numbers could be higher.
Aid is urgently needed in remote areas, relief agencies say
Mr Rezaie told the AFP news agency that thousands of people were facing a shortage of food in remote villages.
"It is a serious challenge - if not taken care of it will cause a human catastrophe," he said.
Another aid agency, World Vision, which runs clinics in Ghor, said 28,000 people in the province were at risk from cold and disease.
Aid workers say helicopters should be sent urgently to snowbound remote areas to assess the situation and provide relief.
Afghan Public Health Minister Mohammad Amin Fatimie says most of the children who died were suffering from respiratory infections, pneumonia and whooping cough caused by the intense cold.
Earlier this month, the bad weather was thought to be responsible for the crash of a Kam Air aircraft on its way from the western city of Herat.
The plane lost contact with air traffic controllers on its approach to Kabul airport as it flew into a heavy snowstorm.
It took several days before soldiers, braving deep snow and possible landmines, reached the crash site high up in the mountains.
Most of the 104 people on board the plane were Afghans. The dead also included about 20 foreigners.