In this 2014 file photo, a Syrian refugee girl sits in a classroom at a Lebanese public school where only Syrian students attend classes in the afternoon, at Kaitaa village in north Lebanon. UNICEF said in 2016 that one-third of Syrians under the age of 18, or about 3.7 million, were born since an uprising against President Bashar Assad erupted in 2011 and escalated into a civil war. Hussein Malla AP