Last Updated Jan 15, 2016 2:45 PM EST
BEIRUT -- The U.N. children's agency said Friday that it witnessed the death of a teenager who died of starvation "in front of our eyes," as well as several cases of severe malnutrition among children trapped in a besieged Syrian town near Damascus.
Hanaa Singer, UNICEF's representative in Syria, said in a statement that the 16-year-old, identified as Ali, died of malnutrition on Thursday in a clinic in the town of Madaya.
Trucks from the U.N. and other humanitarian organizations entered Madaya on Thursday for the second time in a week after reports of starvation deaths. The town has been under siege for months by government forces.
Two other communities, the villages of Foua and Kfarya in northern Syria, besieged by Syrian rebels were also included in the aid operation.
The death of the teenager as international aid workers were inside Madaya reinforced the scale of the humanitarian catastrophe in the town and other besieged areas.
Another aid worker who entered Madaya, Abeer Pamuk of SOS Children's Villages in Syria, said the situation is so devastating that desperate parents resort to giving children sleeping pills in order to calm their hunger.
"Their parents had nothing to feed them. So they just chose to let them sleep and forget about their hunger," she said in a statement from the group.
"None of the children I saw looked healthy. They all looked pale and skinny. They could barely talk or walk. Their teeth are black, their gums are bleeding, and they have lots of health problems with their skin, hair, nails, teeth," Pamuk added.
The U.N. Security Council is scheduled to hold an emergency meeting Friday at the request of Western countries trying to press Syria's warring parties to lift sieges on towns where hundreds of thousands have been cut off from aid and many are starving.
U.N. Secretary-General Ban Ki-moon called the deliberate starvation of civilians a "war crime" and on Thursday urged both the Syrian government and rebels to end the sieges before the commencement of peace talks scheduled for Jan. 25 in Geneva.
Ban said the United Nations and its humanitarian partners are able to deliver food to only 1 percent of the 400,000 people under siege in Syria, down from 5 percent just over a year ago.
Juliette Touma, an Amman-based UNICEF representative, said the agency's staff who spent close to seven hours in Madaya on Thursday are "terribly shocked."
Her staff saw "pretty horrific scenes" of malnourishment, including among women, children and the elderly, she told The Associated Press.
She added, however, that many felt relief at finally arriving at these hard-to-reach areas. "It is important right now to maintain this humanitarian access ... There are 14 other Madayas" in Syria, she said.
Singer, in the statement, said that at the makeshift hospital UNICEF visited in the town, there were only two doctors and two health professionals working under overwhelming conditions.
Meanwhile Russia, which has been conducting airstrikes in Syria to support its Syrian army allies, said that Russian airplanes dropped 22 metric tons of humanitarian cargo over the eastern city of Deir el-Zour, which has been besieged by the Islamic State of Iraq and Syria, or ISIS, for a year.
The city is contested, with ISIS controlling most of the territory but the Syrian government holding some neighborhoods.
The Russian defense ministry did not say when, or in which part of the city, the aid drop occurred. But the Britain-based Syrian Observatory for Human Rights, an opposition activist group that monitors both sides of the conflict, said the aid was parachuted over neighborhoods controlled by government forces.
Lt.-Gen. Sergei Rudskoi of the Russian military's General Staff said that to date most of the aid delivered by international groups had been sent to areas under the rebel control and most of it had fallen into the hands of extremists.