A/HRC/7/12 page 15 2. Detention and expulsion 41. Migrants are particularly vulnerable to detention, or restriction on their freedom of movement/deprivation of their liberty, usually through enforced confinement, either in the receiving country or during transit (by land or sea). In the interception of migrants lacking documentation, many States employ administrative detention of irregular migrants in connection with violations of immigration laws and regulations, which are not considered to be a crime and may include, inter alia, overstaying a permit or non-possession of valid identification or visa documents. The objective of administrative detention is to guarantee that another administrative measure, such as deportation or expulsion, can be implemented. Sometimes administrative detention is also employed on the grounds of public security and public order, inter alia, or when an alien is pending a decision on refugee status or on admission to or removal from the State.31 42. In some cases, however, national immigration regulations are often made into measures that criminalize and punish in an attempt to discourage irregular migration. Undocumented migrants therefore become particularly vulnerable to criminal procedures, which are by definition punitive in nature, for many of the same infractions as administrative detention would encompass, such as irregularly crossing the State border, leaving a residence without authorization, or breaching or overstaying conditions of stay. 43. The Working Group on Arbitrary Detention holds the view that criminalizing the irregular entry into a country exceeds the legitimate interest of States to control and regulate irregular immigration and can lead to unnecessary detention.32 Moreover, often irregular migrants detained for immigration offences considered a criminal offence by the receiving State should be given the opportunity to appeal before an independent judiciary, but are not afforded such protection in practice. In such cases, detention of migrants may become arbitrary.33 Arbitrary arrest and detention is expressly prohibited in international and regional human rights law and migrants’ nationality or lack of legal status in the destination country cannot excuse States from their obligations under international law to ensure due process guarantees and dignified and humane treatment while migrants are held in detention. 31 Much of this section draws from the work of the former Special Rapporteur on the human rights of migrants, Gabriela Rodríguez Pizarro and the work of the Working Group on Arbitrary Detention. See OHCHR, “Administrative detention of migrants”, Migration Discussion Papers, http://www2.ohchr.org/english/issues/migration/taskforce/disc-papers.htm based on report E/CN.4/2003/85. 32 See report of the Working Group on Arbitrary Detention, E/CN.4/1999/63 of 18 December 1998. 33 OHCHR, Fact Sheet No. 26, The Working Group on Arbitrary Detention, http://www.unhchr.ch/html/menu6/2/fs26.htm#IV, pursuant to resolution 1991/42, as clarified by resolution 1997/50.