Tens of thousands of Syrians are at risk of dying from starvation because of the ongoing conflict in the country.
One of the hardest-hit towns is Madaya, located near the Lebanese border.
Doctors Without Borders reports that 23 people who have arrived in one of its health centers have died of starvation since Dec. 1.
The humanitarian organization said that of the 23 people that died, six were under the age of 1 and five were over the age of 60.
The United Nations put out a statement on Thursday saying that it had "received credible reports of people dying from starvation and being killed while trying to leave."
"The ongoing conflict continues to hamper the humanitarian response and freedom of movement is restricted by the presence of armed actors and landmines," the UN said.
The last time that a shipment of food and supplies was delivered to Madaya occurred on Oct. 18, the UN said.
The Associated Press reports that a snowstorm is making conditions even more difficult to deliver supplies.
Some doctors in nearby health centers are using medical syrups to feed the starving.
"Now that the siege has tightened, the doctors we support have empty pharmacy shelves and increasing lines of starving and sick patients to treat," Doctors Without Borders Director of Operations Brice de le Vingne said in the press release. "Medics are even resorting to feeding severely malnourished children with medical syrups as they are the only source of sugar and energy, thereby accelerating the consumption of the few remaining medical supplies."
"Madaya is now effectively an open air prison for an estimated 20,000 people, including infants, children and elderly. There is no way in or out, leaving the people to die," de le Vingne continued.