1 The steady increase in the number of persons that the ICRC visits in detention can be seen in the ICRC's annual reports for 2011–2016, available at: www.icrc.org/en/annual-report (all internet references were accessed in October 2017).

2 For a comprehensive analysis of the humanitarian concerns regarding conditions of detention and persons with specific needs, see ICRC, “Strengthening Legal Protection for Persons Deprived of their Liberty in relation to Non-International Armed Conflict: Regional Consultations 2012”, Background Paper, 2013, pp. 6–7, available at: www.icrc.org/eng/assets/files/2013/strengthening-legal-protection-detention-consultations-2012-2013-icrc.pdf.

3 See ibid., pp. 10–11.

4 See ibid., p. 15.

5 ICRC, Strengthening Legal Protection for Victims of Armed Conflicts, Geneva, 2011, p. 7, available at: www.icrc.org/eng/assets/files/red-cross-crescent-movement/31st-international-conference/31-int-conference-5-1-1-report-strength-ihl-en.pdf.

6 For a more detailed analysis, see below.

7 32nd International Conference, Resolution 1, 32IC/15/R1, 2015 (Resolution 1), para. 8, available at: http://rcrcconference.org/wp-content/uploads/2015/04/32IC-AR-Persons-deprived-of-liberty_EN.pdf.

8 In addition, especially in traditional NIACs taking place solely on the territory of the detaining State, national constitutions or national law often provide essential safeguards for persons deprived of their liberty.

9 Indeed, States have faced legal challenges to their detention practices before domestic or regional courts. A well-known case is UK Supreme Court, Serdar Mohammed v. Ministry of Defence and Others, [2017] UKSC 2, 17 January 2017. For additional references to national case law, see Winkler, Thomas, “The Copenhagen Process and the Copenhagen Process Principles and Guidelines on the Handling of Detainees in International Military Operations”, Journal of International Humanitarian Legal Studies, Vol. 5, No. 1–2, 2014 CrossRefGoogle Scholar.

10 While all States are bound by Article 3 common to the four Geneva Conventions and customary IHL, Additional Protocol II (AP II), for example, is not universally ratified.

11 See T. Winkler, above note 9, p. 260.

12 Deeks, Ashley S., “Administrative Detention in Armed Conflict”, Case Western Reserve Journal of International Law, Vol. 40, No. 3, 2009, p. 434 Google Scholar.

13 For the principles, their commentary, and a summary of the process, see Oswald, Bruce, “The Copenhagen Principles, International Military Operations and Detentions”, Journal of International Peacekeeping, Vol. 13, 2013 Google Scholar.

14 Paragraph IX of the Copenhagen Principles and Guidelines’ preamble clarifies: “The Copenhagen Process Principles and Guidelines are intended to apply to international military operations in the context of non-international armed conflicts and peace operations; they are not intended to address international armed conflicts.”

15 Resolution 1, above note 7, para. 8.

16 It does not consider law enforcement operations below the armed conflict threshold.

17 United Nations Standard Minimum Rules for the Treatment of Prisoners, E/CN.15/2015/L.6/Rev.1, 21 May 2015 (Mandela Rules).

18 It is generally accepted that IHRL continues to apply in times of armed conflict. See, for instance, International Court of Justice (ICJ), Legality of the Treat or Use of Nuclear Weapons, Advisory Opinion, 1996, para. 25; ICJ, Legal Consequences of the Construction of a Wall in the Occupied Palestinian Territory, Advisory Opinion, 2004, para. 106; ICJ, Case Concerning Armed Activities on the Territory of the Congo (DRC v. Uganda), 2005, para. 116. This view has also been taken by the UN Human Rights Committee (HRC), the European Court of Human Rights (ECtHR) and the Inter-American Court of Human Rights. See also ICRC, International Humanitarian Law and the Challenges of Contemporary Armed Conflicts, Geneva, 2011, pp. 13–22, available at: www.icrc.org/eng/resources/documents/report/31-international-conference-ihl-challenges-report-2011-10-31.htm.

19 For example, during the ICRC-facilitated consultation process in 2012–15, States expressed differing views on the conceptual question of whether and to what extent human rights law applies in various types of NIACs. ICRC, Strengthening International Humanitarian Law Protecting Persons Deprived of Liberty: Concluding Report, Geneva, 2015 (ICRC Concluding Report), p. 19, available at: http://rcrcconference.org/wp-content/uploads/2015/04/32IC-Concluding-report-on-persons-deprived-of-their-liberty_EN.pdf.

20 Prisoners of war are defined under Article 4 of GC III as well as Article 44 of AP I.

21 Protected persons are defined under Article 4 of GC IV. See also Article 73 AP I.

22 See AP I, Arts 72–79.

23 See GC III, Art. 21(1); GC IV, Arts 42(1), 78(1).

24 Article 5(2) of GC III only provides that in case of doubt as to whether a person qualifies as a PoW, that person shall enjoy the protection of GC III until such time as his or her status “has been determined by a competent tribunal”. In contrast, GC IV requires that interned persons shall be entitled to have the initial decision to intern reviewed as soon as possible, followed by biannual periodic reviews. See GC IV, Arts 43(1), 78(2).

25 PoWs “shall be released and repatriated without delay after the cessation of active hostilities”: GC III, Art. 118(1). Civilian internees “shall be released … as soon as the reasons which necessitated [their] internment no longer exist”, or “as soon as possible after the close of hostilities”. See GC IV, Arts 46(1), 132(1), 133(1); AP I, Art. 75(3). For more substantive discussion on internment in IAC, see ICRC, “Internment in Armed Conflict: Basic Rules and Challenges”, Opinion Paper, Geneva, November 2014, pp. 3–6, available at: www.icrc.org/en/document/internment-armed-conflict-basic-rules-and-challenges; and the presentation of existing IHL protections contained in a background document prepared for government expert consultations in 2014: ICRC, Thematic Consultation of Government Experts on Grounds and Procedures for Internment and Detainee Transfers, Working Document, Geneva, 2014, available at: www.icrc.org/eng/assets/files/2015/consultation-internment-detainee-transfers-apr-2015.pdf.

26 See, in particular, GC III, Arts 13–14; GC IV, Arts 27–28, 31–34; AP I, Art. 75(2).

27 For a comprehensive presentation of protections contained in the IHL of IAC, see ICRC, Thematic Consultation of Government Experts on Conditions of Detention and Particularly Vulnerable Detainees, Working Document, Geneva, 2014, available at: www.icrc.org/eng/assets/files/publications/icrc-002-4230.pdf.

28 Regarding women, see GC IV, Arts 89(5), 97(4), 132(2); Jean-Marie Henckaerts and Louise Doswald-Beck (eds), Customary International Humanitarian Law, Vol. 1: Rules, Cambridge University Press, Cambridge, 2005 (ICRC Customary Law Study), Rules 119, 134. Regarding children, see GC IV, Arts 81(3), 82(2), 89(5), 94(2), 94(3); ICRC Customary Law Study, Rules 120, 135. See also see ICRC, above note 27.

29 GC III, Art. 12(2)-(3); GC IV, Art. 45(2).

30 GC IV, Art. 45(4).

31 See ICRC Concluding Report, above note 19, p. 10. Indeed, as stated in the report, “States participating in the Resolution 1 consultation process did not point to any specific areas of IHL applicable to IAC-related detention that were in need of strengthening”. Nonetheless, some States voiced an interest in also strengthening IHL protecting detainees in IAC.

32 For a comprehensive analysis of fundamental obligations under common Article 3, see ICRC, Commentary on the First Geneva Convention: Convention (I) for the Amelioration of the Condition of the Wounded and Sick in Armed Forces in the Field, 2nd ed., Geneva, 2016 (Commentary on GC I), paras 581–716. See also Pejic, Jelena, “The Protective Scope of Common Article 3: More than Meets the Eye”, International Review of the Red Cross, Vol. 93, No. 881, 2011 CrossRefGoogle Scholar.

33 Commentary on GC I, above note 32, para. 708.

34 AP II, Arts 4, 5, 6.

35 AP II, Arts 5, 4(3)(a).

36 As defined in Article 1 of AP II, the Protocol shall apply only to NIACs “which take place in the territory of a High Contracting Party between its armed forces and dissident armed forces or other organized armed groups which, under responsible command, exercise such control over a part of its territory as to enable them to carry out sustained and concerted military operations and to implement this Protocol”. Thus, AP II would not apply to NIACs fought only between non-State armed groups, or to conflicts in which the non-State party does not control any territory.

37 ICRC Concluding Report, above note 19, p. 13.

38 See ICRC Customary Law Study, above note 28, Rules 87–99.

39 See ibid., Rules 100–103.

40 See ibid., Rules 118–128.

41 ICRC, above note 5, p. 7.

42 ICRC, above note 18, p. 17. For its part, the ECtHR interpreted the European Convention on Human Rights (ECHR) “in a manner which takes into account the context of the applicable rules of international humanitarian law”. ECtHR, Case of Hassan v. The United Kingdom, Application No. 29750/09, Judgment, 16 September 2014, paras 101–106. This does not mean, however, that IHRL cannot complement IHL.

43 See, for instance, Article 9 of the International Covenant on Civil and Political Rights (ICCPR), Article 5 of the ECHR, Article 7 of the American Convention on Human Rights, and Article 14 of the Arab Charter on Human Rights.

44 See, for example, Mandela Rules, above note 17; United Nations Rules for the Treatment of Women Prisoners and Non-Custodial Measures for Women Offenders, UN Doc. E/RES/2010/16, 22 July 2010 (known as the Bangkok Rules); United Nations Standard Minimum Rules for the Administration of Juvenile Justice, GA Res. 40/33, UN Doc. A/40/53, 1985 (known as the Beijing Rules).

45 See, for example, ECtHR, Hassan, above note 42, paras 74–80; ICJ, Wall, above note 18, paras 107–113.

46 See, for instance, HRC, Fourth Periodic Report: United States of America, CCPR/C/USA/4, 22 May 2012, paras 505–509; Working Group on Arbitrary Detention, The Draft Basic Principles: Comments by the Government of Canada, 28 April 2015, paras 4–8; Working Group on Arbitrary Detention, The Draft Basic Principles: Comments by the Government of Australia, 17 March 2015, paras 2–6.

47 See derogations by Ukraine, France, and Turkey from the ECHR and the ICCPR. In addition, the UK announced in 2016 that it would introduce “a presumption to derogate from the European Convention on Human Rights … in future conflicts”. See: www.gov.uk/government/news/government-to-protect-armed-forces-from-persistent-legal-claims-in-future-overseas-operations.

48 See, for example, Article 4 of the ICCPR and Article 15 of the ECHR. See also HRC, ” CCPR General Comment No. 29: Article 4: Derogations during a State of Emergency”, UN Doc. CCPR/C/21/Rev.1/Add.11, 2001.

49 See note 44 above. Such standards are frequently invoked to interpret more general provisions on humane treatment of detainees in human rights treaties. See, for instance, HRC, “CCPR General Comment No. 21: Article 10 (Humane Treatment of Persons Deprived of Their Liberty)”, UN Doc. HRI/GEN/1/Rev.9, 1992.

50 The Mandela Rules, above note 17, are silent on whether or not they apply in times of armed conflict. Traditionally, the Standard Minimum Rules have been understood as applying to criminal-law prisoners held in regular penitentiary institutions, but they were amended to apply to “persons arrested or imprisoned without charge” (see amendment approved in ECOSOC Res. 2076 (LX1I), 13 May 1977). For its part, the UN Body of Principles for the Protection of All Persons under Any Form of Detention or Imprisonment only applies to “all persons within the territory of any given State”, which excludes extraterritorial detention or detention by non-State forces.

51 It is reported that during the recent revision process, the question of whether the Mandela Rules’ scope of application should be extended was set aside because issues such as “the interaction of international humanitarian and human rights law in the context of dealing with persons deprived of their liberty … could have also led to an impasse, possibly even endangering the completion of the revision process”. Tiroch, Katrin, “Modernizing the Standard Minimum Rules for the Treatment of Prisoners – A Human Rights Perspective”, Max Planck Yearbook of United Nations Law, Vol. 19, No. 1, 2016, p. 299 Google Scholar.

52 Mandela Rules, above note 17, Preliminary Observation 2(1).

53 However, it is also true that in a number of contexts, including States not involved in armed conflict, State administrations, including their judicial systems, are not well-functioning and are often unable to provide all necessary protections in practice.

54 ICRC, above note 18, p. 17. For examples of how Colombia has applied a criminal-law/IHRL approach to detention in the context of a NIAC, see Hill-Cawthorne, Lawrence, Detention in Non-International Armed Conflict, Oxford University Press, Oxford, 2016, pp. 165–166 Google Scholar.

55 Marco Sassòli, “Legal Framework for Detention by States in Non-International Armed Conflict”, Proceedings of the Bruges Colloquium, 16–17 October 2014, p. 65, available at: https://archive-ouverte.unige.ch/unige:77195.

56 For discussion of recent practice, see, for example, Henckaerts, Jean-Marie and Wiesener, Cornelius, “Human Rights Obligations of Non-state Armed Groups: A Possible Contribution from Customary International Law?”, in Kolb, Robert and Gaggioli, Gloria (eds), Research Handbook on Human Rights and Humanitarian Law, Elgar, Cheltenham, 2013, pp. 146–169 CrossRefGoogle Scholar; Rodenhäuser, Tilman, “International Legal Obligations of Armed Opposition Groups in Syria”, International Review of Law, No. 2, 2015 CrossRefGoogle Scholar.

57 In the ICRC's view, however, in “cases in which a group, usually by virtue of stable control of territory, has the ability to act like a state authority …, its human rights responsibilities may … be recognized de facto”. See ICRC, above note 18, pp. 14–15.

58 For some discussion on armed groups’ capacity to provide judicial process, see Commentary on GC I, above note 32, paras 689–695.

59 Given that any outcome of this process will be of a legally non-binding nature, it cannot alter States’ IHRL obligations.

60 31st International Conference, Resolution 1, 31IC/11/R1, 2011, para. 6.

61 The identified options and the ICRC's recommendations were submitted to the International Conference in the ICRC Concluding Report, above note 19, in June 2015.

62 Reports on all four meetings are available at: www.icrc.org/en/document/detention-non-international-armed-conflict-consultations-government-experts.

63 See ICRC, above note 2.

64 See ICRC, Strengthening International Humanitarian Law Protecting Persons Deprived of Their Liberty: Synthesis Report from Regional Consultations of Government Experts, Geneva, 2013, pp. 30–31.

65 Documentation on the first meeting is available at: www.icrc.org/en/document/detention-non-international-armed-conflict-first-thematic-consultation-government-experts. Documentation regarding the second meeting is available at: www.icrc.org/en/document/detention-non-international-armed-conflict-second-thematic-consultation-government-experts.

66 For example, regarding food and water, elements of protection on which discussions should focus include the quantity of food, quality of food, customary diet of the detainee, timing of meals, and sufficiency of and access to drinking water. See ICRC Concluding Report, above note 19, pp. 35–36.

67 Ibid., pp. 22–23.

68 Detailed reports of the discussions have been published in the ICRC Thematic Consultation reports cited in above notes 25 and 27.

69 The chair's conclusions are available at: www.icrc.org/en/document/strengthening-compliance-ihl-meeting-all-states-geneva-switzerland-27-29-april-2015.

70 The ICRC has published detailed reports on all State consultations, available at: www.icrc.org/en/document/detention-non-international-armed-conflict-icrcs-work-strengthening-legal-protection-0. The following summary is mainly based on the ICRC Concluding Report, above note 19, pp. 25–31.

71 Ibid., p. 28.

72 Regarding these standards, different views were expressed on what constitutes “imperative reasons of security” with regard to which criteria should be applied to determine membership in an armed group.

73 In this respect, different sources of grounds and procedures were discussed. While in purely internal NIACs domestic law is likely to be of vital importance, different sources might be needed with regard to detention in extraterritorial NIACs.

74 As a matter of practice, States discussed a number of grounds precluding transfer. See ibid., pp. 31–32.

75 Concrete suggestions of how to overcome these challenges are discussed in ibid., pp. 33–35.

76 See, for example, common Article 3, and Article 22(6) of the Second Protocol to the Hague Convention of 1954 for the Protection of Cultural Property in the Event of Armed Conflict, 1999.

77 Resolution 1, above note 7, para. 5.

78 Ibid., para. 8 (emphasis added).

79 Ibid., para. 9.