A/HRC/20/24 workers regardless of their status with the right not be subjected individually or collectively to arbitrary arrest or detention and the right not be deprived of liberty except on such grounds and in accordance with such procedures as are established by law (art. 16, paras. 1 and 4). 6. The fact that a person is irregularly in the territory of a State does not imply that he or she is not protected by international human rights standards. In its general comment No. 31 (2004) on the nature of the general legal obligation imposed on States parties to the Covenant, the Human Rights Committee stated that “the enjoyment of Covenant rights is not limited to citizens of States Parties but must also be available to all individuals, regardless of nationality or statelessness, such as asylum seekers, refugees, migrant workers and other persons, who may find themselves in the territory or subject to the jurisdiction of the State Party.” 7. At the regional level, the right to liberty and security of person is protected by article 6 of the African Charter on Human and Peoples‟ Rights, article 7 of the American Convention on Human Rights, article 14 of the Arab Charter on Human Rights and article 5 of the European Convention for the Protection of Human Rights and Fundamental Freedoms. 2. Exceptional grounds for administrative detention of migrants 8. The Special Rapporteur has noted that States use a wide range of reasons to justify the detention of migrants and some States see irregular migration as a national security problem or a criminal issue, and neglect the human rights issues at stake. Different categories of migrants may be subjected to detention, including migrants who are undocumented or in an irregular situation, asylum-seekers awaiting the outcome of their asylum application and failed asylum-seekers awaiting removal. The Special Rapporteur would like to emphasize that there is no empirical evidence that detention deters irregular migration or discourages persons from seeking asylum. Despite increasingly tough detention policies being introduced over the past 20 years in countries around the world, the number of irregular arrivals has not decreased. This may be due, inter alia, to the fact that migrants possibly see detention as an inevitable part of their journey. 9. In order not to violate the right to liberty and security of person and to protect against arbitrariness, detention of migrants must be prescribed by law and necessary, reasonable and proportional to the objectives to be achieved. Legitimate objectives for detention are the same for migrants as they are for anyone else: when someone presents a risk of absconding from future legal proceedings or administrative processes or when someone presents a danger to their own or public security. 10. Security detention poses particular risks to migrants, who may end up in prolonged or even indefinite detention justified by vague criteria. The Special Rapporteur would like to stress that detention for security purposes may only be imposed after conducting an individual assessment in each case, for the shortest time possible, and in compliance with all procedural safeguards. 11. The International Covenant on Civil and Political Rights does not contain an exhaustive list of accepted grounds for detention, meaning that an assessment must be made on a case-by-case basis. The Human Rights Committee held in communication No. 560/1993, paragraph 9.2, that “the notion of „arbitrariness‟ must not be equated with „against the law‟, but be interpreted more broadly to include such elements as inappropriateness and injustice. Furthermore, remand in custody could be considered arbitrary if it is not necessary in all the circumstances of the case, for example to prevent flight or interference with evidence: the element of proportionality becomes relevant in this context”. 4