United States attacks by unmanned aerial vehicles (UAVs) or drones in Western Pakistan cannot be justified under international law for a number of reasons. First drones launch missiles or drop bombs, the kind of weapons that may only be used lawfully in an armed conflict. Until the spring of 2009, there was no armed conflict on the territory of Pakistan because there was no intense armed fighting between organized armed groups. International law does not recognize the right to kill without warning outside an actual armed conflict. Killing without warning is only tolerated during the hostilities of an armed conflict, and, then, only lawful combatants may lawfully carry out such killing. Members of the CIA are not lawful combatants and their participation in killing persons - even in an armed conflict - is a crime. Members of the United States armed forces could be lawful combatants in Pakistan if Pakistan expressly requested United States assistance in a civil war to end a challenge to Pakistan's civilian government. No express request of this nature has been made. Even if it were made, drone attacks are the wrong tactic in the context of Western Pakistan. The CIA's intention in using drones is to target and kill individual leaders of al-Qaeda or Taliban militant groups. Drones have rarely, if ever, killed just the intended target. By October 2009, the ratio has been about 20 leaders killed for 750-1000 unintended victims. Drones are having a counter-productive impact in Pakistan's attempt to repress militancy and violence. The use of the drone is, therefore, violating the war-fighting principles of distinction, necessity, proportionality and humanity.