"The biggest health challenge we are facing at the moment is the threat posed by the cold," said Richard Munz, health coordinator in Bam for the International Federation of Red Cross and Red Crescent Societies.

He warned that "pneumonia and respiratory tract infections will increase, particularly among vulnerable children," in the current cold conditions.

An estimated 30,000 people were killed in the earthquake on Friday, which flattened the ancient citadel of Bam and left tens of thousands homeless.

Some 40,000 people are still sleeping rough in sub-zero temperatures, in tents set up amid the rubble.

TERRA.WIRE