A/HRC/45/CRP.7 “except on such grounds and in accordance with such procedures as are established by law”.196 Relevant to whether a detention is “arbitrary” or not are factors such as the detention’s legality, appropriateness, proportionality, and reasonableness.197 Persons arrested are to be informed of the reasons for arrest at the time of the arrest and have the right to be promptly informed of any charges.198 Anyone arrested or detained on a criminal charge must be brought promptly before a judge or other officer authorised by law to exercise judicial power, and is entitled to trial within a reasonable period or release.199 Persons have a right to take proceedings before a court for the purposes of reviewing the lawfulness of detention and to be released if the detention is unlawful (with lawfulness being considered both as a matter of domestic and international law).200 150. Under international humanitarian law, a prohibition on “arbitrary detention” arises from the requirement that persons taking no active part in the hostilities are entitled to be treated humanely.201 Arbitrary deprivation of liberty is also prohibited by customary international humanitarian law.202 International humanitarian law treaty law related to NIACs is not explicit concerning the “security detention” of civilians where absolutely necessary for the security of the detaining power (unlike IAC203). However, any such power is likely to be conditioned by similar procedural requirements as apply in IAC, in particular that the person be informed of the reason for detention, is able to challenge the lawfulness of the detention, and that there be initial and periodic reviews by an independent body.204 The procedural guarantees established under international human rights law continue to apply. 151. Yemen is not a party to the International Convention for the Protection of All Persons from Enforced Disappearance (CPED). However, by virtue of its ratification of the ICCPR, Yemen is obliged not to engage in enforced disappearances205 given that the act violates a range of civil and political rights, including a person’s right to recognition as a person before the law,206 and his/her right to liberty and security including freedom from arbitrary detention.207 Enforced disappearances has been described as a “grave threat to life” violating the right to life,208 as well as implicating the prohibition on torture and other cruel, inhuman or degrading treatment.209 152. While enforced disappearance is not referred to explicitly in international humanitarian law treaties, the act of disappearing persons taking no active part in hostilities 196 ICCPR, art. 9(1). Human Rights Committee, A. v. Australia, Communication No. 560/1993, CCPR/C/59/D/560/1993, para. 9.2. Inappropriateness, injustice and lack of predictability may also render arbitrary an otherwise lawful detention; see Human Rights Committee, Van Alphen v. The Netherlands, Communication No. 305/1988, CCPR/C/39/D/305/1988, para. 5.8. 198 ICCPR, art. 9(2). 199 ICCPR, art. 9(3). 200 Human Rights Committee, A. v. Australia, Communication No. 560/1993, CCPR/C/59/D/560/1993, para. 9.5. 201 Additional Protocol II, art. 4(1); Common art. 3 of the Geneva Conventions. See also ICRC Study on Customary International Humanitarian law, rule 99. 202 ICRC Study on Customary International Humanitarian Law, rule 99. 203 Geneva Convention IV, art. 42 (applicable in IAC). 204 See Geneva Convention IV, arts. 43, 78 (applicable in IAC). 205 For the purposes of this report, the Group of Experts has adopted the definition of “enforced disappearance” used in the CPED: ie that an enforced disappearance occurs where there is an “arrest, detention, abduction or any other form of deprivation of liberty by agents of the State or by persons or groups of persons acting with the authorisation, support or acquiescence of the State, followed by a refusal to acknowledge the deprivation of liberty or by concealment of the fate or whereabouts of the disappeared person, which place such a person outside the protection of the law” (art. 2, CPED). It is noted that the Rome Statute uses a slightly different formulation of enforced disappearance in art. 7(2)(i). 206 ICCPR, art. 16. 207 ICCPR, art. 9. 208 ICCPR, art. 6(1). See Human Rights Committee, General Comment No. 36: Article 6: the right to life (2019), para.58. 209 Ibid., ICCPR, art. 7. 197 43