A/HRC/4/42 page 19 that such agreements, including with regard to Ecuador and Colombia,33 have been criticized by local NGOs for not having been properly approved by the national legislatures. The result is that criminal acts by PMSC employees can go unpunished. This is of concern to the Working Group. It notes information received of employees of PMSCs operating under Plan Colombia with allegations of illicit drug and munitions, trafficking and sexual assaults on minors. None of these cases have been treated by the judiciary in Colombia due to the immunity enjoyed by the persons in question. The Working Group notes the need to end the legal loophole of PMSCs as non-State actors, and for States to avoid using PMSCs as means to conduct its policies in impunity. III. THEMATIC ISSUE: THE STATE AS PRINCIPAL HOLDER OF THE USE OF FORCE 56. The Working Group notes that the phenomenon of mercenaries has passed from being an activity of an individual into becoming an activity of wider scope and reach, with private military and security companies lending services that are traditionally and characteristically among the core functions and competencies of the State. This phenomenon is in some cases impeding the enjoyment of human rights. The Working Group is interested in elucidating this surrender of the monopoly of the use of the force on the part of States, and notes that privatization or delegation of security does not diminish the responsibilities of the State under international law.34 57. The Working Group notes the position of several Governments that consider the issue of a mercenary recruitment as an issue of “labour mobility” rather than an issue for prosecution of the crime of mercenarism. In this regard, an argument commonly forwarded is that labour contracts and their acceptance do not concern the State, as these constitute private acts. However, the Working Group reiterates existing State obligations to establish procedures backed by a juridical system to ensure the protection of their nationals, especially in the field of security and labour. 58. The Working Group considers that certain provisions of international human rights instruments require States to protect against violations by both State agents and private persons or entities. Therefore, States must take appropriate steps to prevent, and if not, investigate and punish, violations and harm caused by private entities. States are under a duty to exercise due diligence to prevent and punish abuses also by non-State actors, and States are encouraged to take legislative and other measures to ensure victims have access to effective remedies as determined and enforced by relevant authorities.35 In ensuring due diligence under international 33 Text of bilateral agreement between the Governments of the United States and Colombia, signed on 17 September 2003. 34 See the “Rapport du Conseil fédéral Suisse sur les entreprises de sécurité et les entreprises militaires privées” (pursuant to the postulat Stähelin 04.3267 du 1er juin 2004: Entreprises privées chargées de tâches de sécurité) of 2 December 2005. 35 See CCPR/C/21/Rev.1/Add.13, general comment No. 31 on the nature of the general legal obligation imposed on States parties to the Covenant (2004), para. 8.