The UN 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 the besieged Syrian town of Madaya near Damascus. Doctors Without Borders said later that five people died of starvation after the first UN humanitarian aid convoy since October arrived in Madaya on Tuesday afternoon. 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 Madaya's clinic. Brice de le Vingne, director of operations for the medical aid organization known by its French initials MSF, said it was "shocking" that people were dying despite the arrival of convoys carrying food and medicine. "Some of the current patients may not survive another day," he said. "Medical evacuations for the most critically sick and malnourished need to happen immediately, and it is hard to understand why patients clinging to life have not already been evacuated." MSF said 23 patients died of starvation in Madaya in December, five died on Jan. 10, and two more died on Tuesday as the first convoy was en route. With the five deaths after the convoy's arrival, the total number of deaths from starvation confirmed by the MSF-supported medics in Madaya is 35, MSF said. UN humanitarian chief Stephen O'Brien said Tuesday that about 400 people needed to be evacuated from Madaya for urgent medical treatment. Trucks from the UN 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. UN 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. A UN Security Council meeting Friday to address the sieges exhibited the bitter divisions that have characterized the international response to Syria's war. Russian Deputy Ambassador Vladimir Safronkov, whose country is a close ally of the Syrian government, questioned the motives of France, Britain and the United States, which support the opposition, in convening the meeting in the first place. He called it "unnecessary noise" that could undermine the Geneva talks. Safronkov accused critics of Syria's government of "double standards" by emphasizing the crisis in Madaya while minimizing the suffering in towns besieged by rebels. British Deputy Ambassador Peter Wilson said the Security Council should call on all parties to lift all sieges but he emphasized that the Syrian government "has the primary responsibility to protect Syrians." He said "Madaya is just the tip of the iceberg" and if the "status quo continues, these images that we've seen from Madaya could be repeated many, many times over." In a clear reference to Russia, Wilson said "let Council members with ties to the regime use their influence, and not their air force, to address this horrific situation." Safronkov said Russia is engaging with "the relevant Syrian authorities, prompting them toward constructive cooperation with the United Nations." 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 Daesh group for a year. The city is contested, with IS 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. — AP