A/HRC/37/50 4. Arbitrariness of detention based solely on migration-status 22. Just as any other form of deprivation of liberty, any detention of migrants must be justified for each individual as lawful, necessary and proportionate in the circumstances and, in case of administrative or preventative detention, must be periodically re-assessed as it extends in time.36 Provided that these generic conditions are met on an individual basis, "(a)sylum seekers who unlawfully enter a State party’s territory may be detained for a brief initial period in order to document their entry, record their claims and determine their identity if it is in doubt. To detain them further while their claims are being resolved would be arbitrary in the absence of particular reasons specific to the individual, such as an individualized likelihood of absconding, a danger of crimes against others or a risk of acts against national security. The decision must consider relevant factors case by case and not be based on a mandatory rule for a broad category; must take into account less invasive means of achieving the same ends, such as reporting obligations, sureties or other conditions to prevent absconding; and must be subject to periodic re-evaluation and judicial review. (...) The inability of a State party to carry out the expulsion of an individual (...) does not justify indefinite detention." 37 23. On the particularly issue of migration-related detention of children it has been observed that "offences concerning irregular entry or stay cannot (...) have consequences similar to (...) the commission of a crime. Therefore, the possibility of detaining children as a measure of last resort, which may apply in other contexts such as juvenile criminal justice, is not applicable in immigration proceedings as it would conflict with the principle of the best interests of the child and the right to development."38 Accordingly, the detention of children based solely on their own or their parents' irregular migration status has authoritatively been found to be arbitrary.39 24. Applying this rationale more generally, the Special Rapporteur observes that breaches of immigration laws, as such, are essentially administrative in nature and do not constitute crimes against persons, property, or national security which might justify or require sanctions involving deprivation of liberty.40 Moreover, the Refugee Convention even expressly prohibits the punishment of asylum seekers for having breached immigration rules in order to gain access to the protection of the territorial State.41 25. In sum, therefore, the margins of permissibility of migration-related detention are narrow, both in terms of substantive justification and in terms of duration, and the mere fact that detention is authorized by domestic law does not exclude its arbitrariness under international law. In the view of the Special Rapporteur, criminal or administrative detention based solely on migration status exceeds the legitimate interests of States in protecting their territory and regulating irregular migration and should be regarded as arbitrary.42 5. Relationship between arbitrariness and torture or ill-treatment 26. While not every case of arbitrary detention will automatically amount to torture or illtreatment, there is an undeniable link between both prohibitions. Already more than 30 years ago, the International Court of Justice held that "wrongfully to deprive human beings of their freedom and to subject them to physical constraint in conditions of hardship is in itself manifestly incompatible with the principles of the Charter of the United Nations, as well as with the fundamental principles enunciated in the Universal Declaration of Human Rights".43 36 37 38 39 40 41 42 43 8 CAT, GC_No.4_(2017)_Art.3, §12. CCPR, GC_No.35_(2014), §18. Joint_GC_No.4_(CMW) and No.23_(CRC)_(2017), §10. WGAD, Revised_Deliberation_No.5(AdvEditedVersion_07.02.2018), §40; Joint_GC_No.4(CMW) and No.23_(CRC)_(2017), §5; IACtHR,_OC-21/14(19.08.2014), §154. CMW/C/GC/2 (28.08.2013), §§5, 24; A/HRC/23/46 (24.042013), §47. Art.31(1) Refugee Convention(1951). WGAD, Revised_Deliberation_No.5(AdvEditedVersion_07.02.2018), §10. ICJ, USA_v._Iran, Jgmt(Merits)_24.05.1980, §91.