In addition to rifles, mortars, artillery and suicidal car bombs, ISIS has recently added commercial drones, converted into tiny bombs, into the mix of weapons it uses to fight in Iraq. In October, The New York Times reported that the Islamic State was using small consumer drones rigged with explosives to fight Kurdish forces in Iraq. Two Kurdish soldiers died dismantling a booby-trapped ISIS drone. Several months later and it appears the use of drones on the battlefield is becoming more prevalent. Popular Science reports: Previously, we've seen ISIS scratch-build drones, and as Iraqi Security Forces retook parts of Mosul, they discovered a vast infrastructure of workshops (complete with quality control) for building standardized munitions, weapons, and explosives. These drone bombers recently captured by Iraqi forces and shared with American advisors appear to be commercial, off-the-shelf models, adapted to carry grenade-sized payloads. "It's not as if it is a large, armed UAV [unmanned aerial vehicle] that is dropping munitions from the wings -- but literally, a very small quadcopter that drops a small munition in a somewhat imprecise manner," [Col. Brett] Sylvia, commander of an American military advising mission in Iraq, told Military Times. "They are very short-range, targeting those front-line troops from the Iraqis." Because the drones used are commercial models, it likely means that anti-drone weapons already on hand with the American advisors are sufficient to stop them. It's worth noting that the bomb-dropping drones are just a small part of how ISIS uses the cheap, unmanned flying machines. Other applications include scouts and explosive decoys, as well as one-use weapons. ISIS is also likely not the first group to figure out how to drop grenades from small drones; it's a growing field of research and development among many violent, nonstate actors and insurgent groups. Despite the relative novelty, it's also likely not the deadliest thing insurgents can do with drones.