Starvation is the Syrian government's newest and cruelest weapon against opposition neighborhoods and infants are particularly vulnerable, activists and doctors have alarmed.

Many are starving in the suburbs south of Damascus, leaving infants with swollen heads and distended bodies, their mothers dry of breast milk, and their elders skeletal and dehydrated, CNN reported.

At the National Hospital South of Damascus, 43 people have died of starvation, 22 of them children, the youngest just 23 days old, with most of the deaths occurring this past month, a dramatic increase, according to hospital staff.

Hostilities make it difficult to gain a clear view of the scope and scale of malnutrition in the area, but the WFP estimates at least 800,000 civilians remain under siege.

CNN has shown a number of shocking videos with graphic content, but stressed there is no way to verify their authenticity.