33 Chapter I having covered the legal framework of international human rights law and international humanitarian law in armed conflict, chapter II will focus first on the trigger for their concurrent application, namely the existence of an armed conflict. It will also analyse the current legal understanding of their territorial scope. It will then explain how the exceptional mechanisms known as derogations and limitations as well as the use of reservations to treaties affect their applicability. Finally, it will discuss the problems resulting from their concurrent applicability. A. ARMED CONFLICT AS THE TRIGGER The concurrent application of international human rights and humanitarian law can happen only when a series of objective conditions are met. International humanitarian law being essentially a body of law applicable to armed conflict, the existence of a situation amounting to an armed conflict is necessary to trigger its applicability in conjunction with international human rights law. The next sections will address the question of what an armed conflict is and what types of armed conflict international humanitarian law applies to. It should, however, be noted that a number of international humanitarian law obligations require action before a conflict begins or after a conflict ends. For example, States must provide training in international humanitarian law to their armed forces in order to prevent potential abuse; States must also encourage the teaching of international humanitarian law to the civilian population; domestic legislation must be adopted implementing its relevant provisions, including the obligation to include war crimes in domestic law; States must also prosecute persons who have committed war crimes. One category of war crimes, grave breaches of the Geneva Conventions and of Protocol I, must be prosecuted according to the principle of universal jurisdiction, i.e., independently of where the crime has been committed and of the nationality of the offender and of the victims. Thus, some violations of international humanitarian law could be established and their perpetrators punished outside the time frame and the geographical context of an actual armed conflict.