Across the vast region under IS control, the group is actively conscripting children for battle and committing abuses against the most vulnerable at a young age, according to a growing body of evidence assembled from residents, activists, independent experts and human rights groups. In Syria’s Aleppo province, an activist affiliated with the rebel Free Syrian Army said its fighters encountered children in their late teens “fairly often” in battles against the rival Islamic State group. [...] a United Nations panel investigating war crimes in the Syrian conflict concluded that in its enlistment of children for active combat roles, the Islamic State group is perpetrating abuses and war crimes on a massive scale and “in a systematic and organized manner.” The panel of experts, known as the Independent International Commission of Inquiry on Syria, conducted more than 300 interviews with people who fled or are living in IS-controlled areas, and it examined video and photographic evidence.