In view of the new circumstances and modalities of the criminal acts of illegal armed groups which operate more and more frequently disguised as civilians, the armed forces must undertake all possible efforts to distinguish the civilian population and to protect the civilian population in all circumstances. 

[W]ith regard to the conduct of hostilities, it is important to note that IHL is ruled by fundamental principles, such as the principles of distinction, limitation and proportionality. Indeed, … the principle of distinction imposes on weapon bearers the obligation to distinguish in their military actions between combatants and non-combatants. 

[T]he essential principles of international humanitarian law have acquired ius cogens status, based on the fact that the international community as a whole has recognized their peremptory and imperative nature … Among the essential principles of international humanitarian law with ius cogens status applicable in internal armed conflicts … [is] … the principle of distinction. 

The general duty to distinguish between civilians and combatants is an essential duty binding the parties to any non-international armed conflict to differentiate at all times between civilians and combatants in order to protect civilians and their property. Indeed, parties to a conflict are bound to make every effort to distinguish between military objectives and civilians … This rule is found in international treaties applicable in internal armed conflicts and is binding on Colombia. It forms part of customary international humanitarian law and has attained ius cogens status.  [footnote in original omitted]

In a non-international armed conflict, civilians can take up arms and form armed rebel groups, putting themselves outside the laws of the country. They thus become combatants which the State can attack and fight against with perfect legitimacy. As a result, such rebels are criminals and combatants at the same time. 

These organizations, nurtured by the national government itself, contribute nothing to the immunity of the civilian population, since they involve citizens in the armed conflict, divesting them of their protected status and making them into legitimate targets of attack … In the view of the Ombudsman’s Office, the operation of the Convivir cooperatives means that civilians participate directly in the armed conflict, thereby becoming combatants. 

In Colombia, communal guard and private security services have been created under the name “convivir”. These services take the form of rural security cooperatives composed of individuals whom the State has authorized to bear arms, and who collaborate with the authorities by providing information to the public security forces concerning the activities of the guerrilla organizations. There is a public debate over the question of whether the members of these services should be considered civilians or combatants. 

The principle of distinction is complex and encompasses a number of treaty and customary norms applicable in internal armed conflicts, in addition to, in many cases, enjoying ius cogens status. These rules [include] … the prohibition of direct attacks against the civilian population. 

Prohibited attacks are those where the primary objective is the civilian population. In order to determine whether an attack has been directed against the civilian population, international case law has taken into account factors such as: the means and methods employed for the attack, the number and status of the victims, the nature of the crimes committed during the attack, the resistence encountered, and the extent to which the attacking force complied or attempted to comply with the precautionary principle under international humanitarian law. It is not required that the attack be directed toward the civilian population as a whole in the geographic location where the events occur. But it must be proven that the attack was not directed against a limited number of individuals.  [footnotes in original omitted]

The prohibition of indiscriminate attacks … is directly related to the prohibition of direct attacks against the civilian population, so much so that the International Criminal Tribunal for the former Yugoslavia has classified the commission of attacks using indiscriminate means as attacks directed against civilians.  [footnote in original omitted]