How did ISIS use commercial drones during the Battle of Mosul in 2016–17?

During the battle for Mosul, Iraq (2016–17), ISIS utilized commercially available drones to drop small munitions on Iraqi forces. This tactic represented one of the earliest instances of a non-state actor performing large-scale military adaptations of commercial drone technology.1

Beyond direct strike missions, militant groups like ISIS have employed these drones for a variety of purposes, including:

• Reconnaissance: Monitoring enemy positions and movements.12
• Coordination: Assisting in the planning and execution of complex attack operations.1
• Psychological Operations: Utilizing drones for propaganda and to induce fear among opposing forces and civilian populations.12

The adaptation of off-the-shelf quadcopters and fixed-wing drones by insurgent groups has disrupted traditional military asymmetries, allowing non-state actors to challenge technologically superior adversaries at a relatively low cost. This democratization of drone warfare presents significant ethical and legal challenges, particularly regarding the principles of distinction and proportionality under international humanitarian law.12