Syria’s bloody armed conflict has led to a humanitarian crisis with millions internally displaced or seeking refuge in neighboring countries. The government and pro-government militias have attacked heavily populated areas, killing civilians with indiscriminate weapons such as cluster munitions and barrel bombs. Government forces have also arbitrarily arrested, forcibly disappeared, and tortured people, many of whom died in detention. Non-state armed groups opposing the government have also carried out serious abuses including deliberate and indiscriminate attacks on civilians, use of child soldiers, kidnapping, and torture in detention. Extremist groups Islamic State, also known as ISIS, and Jabhat al-Nusra, Al-Qaeda’s affiliate in Syria, are responsible for systematic and widespread abuses.