A/HRC/32/41 and crimes against humanity and specifically addresses grave forms of sexual violence, including rape, sexual slavery, enforced prostitution, forced pregnancy or enforced sterilization. Also of relevance are the instruments of international humanitarian law that prohibit certain conduct in the context of international and non-international armed conflict, including slavery, sexual slavery, sexual violence and forced labour. It is important to note, however, that trafficking itself, and the gender-based harm with which it is associated, has never been explicitly prohibited, or even regulated, by international humanitarian law. This despite the fact that, as shown previously, many of the worst practices associated with armed conflict, such as the forced recruitment of child soldiers, the organized sexual enslavement of women and the enlistment of civilians into forced or highly exploitative labour, could also fall within the international legal definition of trafficking. However, international instruments have been interpreted in accordance with evolving human rights norms and standards through the jurisprudence of the international tribunals. 48. Other accepted sources of international law, such as State practice, custom and the decisions of international tribunals, can also be relevant when determining exactly what is required of States with respect to their response to trafficking in situations of conflict. In relation to custom, for example, the prohibition on slavery is recognized to be a part of customary international law, binding on all States irrespective of whether they have actually become party to one or more treaties that specifically prohibit slavery in all situations, including in conflict. The prohibition on forced labour of civilians has also been identified as a rule of customary international humanitarian law (see para. 53 below). Examples of judgments of international tribunals that have helped to shape the international legal framework include Rantsev v. Cyprus and Russia, decided by the European Court of Human Rights in 2010, which is relevant to State responsibility to investigate and prevent trafficking, and the decision by the International Tribunal for the Former Yugoslavia in Prosecutor v. Kunarac et al. (2001) convicting the defendants of enslavement as a crime against humanity. 49. Finally, several soft law instruments reflect and contribute to the relevant international legal framework. These include the principles and guidelines on human rights and human trafficking recommended by the United Nations High Commissioner for Human Rights; UNHCR guidelines on trafficking and asylum; resolutions of the General Assembly and the Human Rights Council; findings and reports of international human rights mechanisms such as treaty bodies and special procedures; and non-treaty agreements between countries regarding issues such as the repatriation and reintegration of trafficked persons as well as between the United Nations and Member States on matters relating to peacekeeping. Laws and instruments that address specific violations related to trafficking in conflict and post-conflict situations 50. Prohibition on trafficking and migration-related exploitation. International law requires States to criminalize and penalize a range of conduct related to trafficking. The obligation to criminalize trafficking when committed intentionally is set out in article 5 of the Protocol to Prevent, Suppress and Punish Trafficking in Persons, Especially Women and Children, supplementing the United Nations Convention against Transnational Organized Crime. Most States (168, as at October 2015) are party to the Protocol and thereby bound by this obligation. Many States are also bound by one or more of the regional trafficking treaties, such as the Council of Europe Convention and the European Union Directive cited above, which impose identical obligations. 51. Prohibition on enslavement, including slavery. International law prohibits slavery, servitude and practices similar to slavery, including debt bondage and serfdom, and servile forms of marriage and exploitation of children. The prohibition on slavery (defined 13