Thousands of people are under siege from forces loyal to Bashar al Assad, with "two or three" dying of starvation every day.
Residents of a besieged Syrian town have been forced to eat cats and dogs as thousands of people face starving to death.
Madaya was once a popular holiday resort for Syrians, but is now under siege from forces loyal to the government of Bashar al Assad and Lebanon's Hezbollah movement.
Thousands are now trapped, with many saying they have no food, water or electricity.
A picture posted on a Facebook page detailing the suffering in the town showed a picture of of someone seemingly preparing to slit the throat of a cat.
Alongside the caption read: "Because it's just what's left for us."
An unnamed aid worker in the town confirmed that some residents were eating cats and dogs to survive, while others ate leaves.
"Humanity has fallen with the fall of the first man from hunger in Madaya," he said.
Families were also forced to eat grass and drink water flavoured with jam or spices.
Another picture of the Facebook page showed a plate of water with something green in it which the user said was "water, water, salt, salt, lemon ... a meal for two".
Rice is sold by the gramme because a kilogramme can cost up to £170.
Dr Mohamad Youssef, who acts as the manager of the medical council in Madaya, said two or three residents are dying of starvation every day.
"The death toll is striking mostly the elderly, the women and children," he said.
"The medical staff are on high alert 24 hours. They are receiving people who are severely ill and fainting all hours - day and night."
The International Committee of the Red Cross (ICRC) said it hoped to get aid to all three villages in the next few days.
Madaya is just 15 miles from Damascus, and less than seven miles from the border with Lebanon.
In mid-October, more than 20 lorries were allowed to deliver medical and humanitarian supplies but the situation has reportedly worsened since then.
The UK-based Syrian Observatory for Human Rights, said on Monday that 10 people had died because of lack of food in recent weeks.
The monitoring group added that 13 others had been shot by pro-government forces or blown up by mines while trying to find food.
The UN has said that the apparent use of siege warfare has been used in clear breach of international laws.