The United Nations is expected to send a convoy with humanitarian aid for as many as 40,000 civilians in Syria's Madaya town, where a six-month-long siege by government forces and Hezbollah militants has deprived the people of medical and food supplies.

"I have just got confirmation that our humanitarian convoy will leave tomorrow (Monday) morning," UN refugee agency spokesperson Melissa Fleming told the BBC.

"We are pretty confident," she said.

In the wake of lack of food supplies in Madaya, which is located 40 kms from Damascus, people have reportedly resorted to consuming grass and pets.

An aid convoy of the World Food Programme (WFP) with medicines and food supplies was supposed to reach Madaya on Sunday, but it was reportedly delayed due to "logistical reasons".

"The distribution of aid will not take place on Sunday for logistical reasons; we are working hard for it to take place on Monday," ABC News quoted Pawel Krzysiek -- the spokesperson for the International Committee of the Red Cross in Damascus -- as saying.

Over 250 people in Madaya are fighting "acute malnutrition" and at least "10 of them need immediate medical evacuation", Brice de la Vigne from the Medecins Sans Frontieres (MSF) medical charity told BBC.

The Syrian Observatory For Human Rights had, on 30 December, released a report suggesting at least 1,200 cases of chronic medical conditions. The Observatory's report said that at least 300 children are suffering from malnutrition and different medical conditions.