They had been throwing stones along with dozens of others near the border.
They had been throwing stones along with dozens of others near the border.
16-year-old identified as Ali passed away on Thursday in Madaya's clinic of severe malnutrition.
More than two dozen people have reportedly starved to death since December.
The attack which lasted for more than an hour killed at least 18 people and wounded 50.
Talks were under way to evacuate 400 Syrians, mostly women and children, from a hospital in Madaya.
The talk is likely to be held on January 10.
More than 260,000 people have been killed in Syria since the conflict began in March 2011 with anti-government demonstrations.
Russia began carrying out air strikes on the positions of Daesh fighters in September in support of Assad's army.
25 people wounded, 50-75 hostages taken by gunmen in the shopping centre.
Red Crescent trucks carrying food and medical supplies travelling with UN vehicles entered Madaya near the Lebanese border.