(International Business Times) -The latest development in the battle to retake Mosul from Islamic State (Isis) is one that has shocked the world. More than 300 IS (Daesh) child soldiers, known as ‘Caliphate Cubs’, were killed as US-backed Iraqi forces advanced into the country’s city, which was once the heart land of the terror group’s territory. Though the use of child soldiers was a scandalous revelation, security analysts and researchers argue it is nothing new in the context of warfare.