A/HRC/43/56 particularly those involved in law enforcement.276 For State investigations to be effective, they must be as prompt as possible, exhaustive, impartial, independent and open to public scrutiny.277 The African Commission on Human and Peoples’ Rights has explained that a “state can be held responsible for killings by non-state actors if it approves, supports or acquiesces in those acts or if it fails to exercise due diligence to prevent such killings or to ensure proper investigation and accountability”.278 11. The government of South Sudan bears the primary duty to protect and safeguard the well-being of its citizens through obligations it has voluntarily assumed under both domestic and international law. Non-state actors (“armed groups”) may not be parties to such international human rights treaties, though are nevertheless obligated to respect the fundamental human rights of persons when such actors exercise de facto control over territory or persons, and such groups have additional obligations under international humanitarian law in times of armed conflict.279 C. Starvation 12. Protection of the population from starvation is a well-established norm under both treaty and customary international law binding on all belligerents, including non-state actors. Customary and treaty law prohibit impeding or the diversion of humanitarian assistance. South Sudan is a state party to the four Geneva Conventions of 1949 and the three Additional Protocols of 1977 and 2005.280 Of particular relevance to the non-international armed conflict in South Sudan are Common Article 3 to the Geneva Conventions and Articles 14 and 18 of Additional Protocol II to the Geneva Conventions, which prohibit the starvation of civilians or rendering useless objects indispensable for their survival and diversion of humanitarian assistance. Once the threshold for the application of Common Article 3 to the 1949 Geneva Conventions has been reached, the provisions which operate to protect the victims of war continue to apply even when there may appear to be periods of calm. 281 13. All parties to the conflict in South Sudan are bound by the relevant rules of customary international law applicable in non-international armed conflict.282 These include requirements that parties to such conflicts must at all times abide by the principles of distinction, proportionality and precaution in attack. 283 Belligerents have an obligation to ensure that civilians are humanely treated and to hold criminally accountable those individuals and entities who may be responsible for violations of this obligation. 14. The Republic of South Sudan is bound by Article 25 of the Universal Declaration of Human Rights which guarantees the right to food as part of an adequate standard of living. As a state party is also bound by the provisions of the African Charter on Human and Peoples approved, supported or acquiesced in those acts. See also the Report on the Commission of Inquiry on Burundi, September 2017 (A/HRC/36/54), paragraphs 23-27. 276 See the United Nations Principles on the Effective Prevention and Investigation of Extra-Legal, Arbitrary and Summary Executions, adopted on 24 May 1989 by the Economic and Social Council Resolution 1989/65, paragraphs 9, 10, 17. 277 See, for example, Basic Principles and Guidelines on the Right to a Remedy and Reparation for Victims of Gross Violations of International Human Rights Law and Serious Violations of International Humanitarian Law, 2005. 278 Paragraph 9 of General Comment No. 3 on the African Charter on Human and Peoples’ Rights: The Right to Life (Article 4), adopted during the 57th Ordinary Session of the African Commission on Human and Peoples’ Rights held from 4 to 18 November 2015 in Banjul, The Gambia. 279 See for a full discussion the Commission’s 2018 Report A/HRC/37/CRP.2, paras. 99-137. 280 South Sudan ratified the Four Geneva Conventions and their Additional Protocols on 25 January 2013; they entered into force for South Sudan on 25 July 2013. 281 The ICRC 2016 Commentary on the First Geneva Convention (Cambridge, Cambridge University Press, 2016) on the criteria of intensity and organization required for Article 3 to be applicable, see p. 141, para. 387; pp. 174-175, paras. 414-444, 484. See also Gabriella Venturini, “The Temporal Scope of the Conventions”, in A. Clapham, P. Gaeta, and M. Sassòli, (eds), The 1949 Geneva Conventions: A Commentary, (Oxford, Oxford University Press, 2015) 51-66, at 61. 282 ICRC, Study on Customary International Humanitarian Law, Rules 1-24. 283 Ibid. 48