Rights of the child A/RES/71/177 63. Notes with concern that there are many cases of unaccompanied children going missing every year, and encourages States to sufficiently investigate all cases of missing unaccompanied children and take all measures necessary to increase their protection, including by, inter alia, enhancing national capacities to identify, register and document new arrivals; 64. Recognizes the particular vulnerability of migrants in transit situations, especially children, including through national borders, and the need to ensure full respect for their human rights in these circumstances also; 65. Urges States to ensure that repatriation mechanisms allow for the identification and special protection of persons in vulnerable situations, including all migrant children, and to take into account, in conformity with their international obligations and commitments, the principle of the best interests of the child, clarity of reception and care arrangements and family reunification; 66. Encourages States to put in place, if they have not yet done so, appropriate systems and procedures to ensure that the best interests of the chil d are a primary consideration in all actions or decisions concerning migrant children, regardless of their migration status, and to use alternatives to the detention of migrant children; 67. Underlines that children, including adolescents, should not be subject to arbitrary arrest or detention based solely on their migration status and that the deprivation of the liberty of migrant children and adolescents should be a measure of last resort, under conditions that respect the human rights of each child and in a manner that takes into account, as a primary consideration, the best interests of the child; 68. Reaffirms that all individuals who have crossed or are seeking to cross international borders are entitled to due process in the assessment of their le gal status, entry and stay, also reaffirms that States will consider reviewing policies that criminalize cross-border movements and will also pursue alternatives to detention while these assessments are under way, and recognizes that detention for the purposes of determining migration status is seldom, if ever, in the best interests of the child and that States will use it only as a measure of last resort, in the least restrictive setting, for the shortest possible period of time, under conditions that respect their human rights and in a manner that takes into account, as a primary consideration, the best interests of the child, and will work towards the ending of this practice; 69. Encourages States to develop or enhance early childhood programmes targeted at assisting families facing especially difficult circumstances, including those headed by single parents or children, those living in the most vulnerable and disadvantaged situations and those living in extreme poverty or caring for children with disabilities; 70. Recognizes the importance of coordinating efforts among countries of origin, transit and destination, while also recognizing their roles and responsibilities to address the irregular migration of unaccompanied children and to safeguard their human rights, with due consideration for the protection of the best interests of the child; 71. Requests States to adopt concrete measures to prevent the violation of the human rights of migrants while in transit, including in ports and airports and at borders and migration checkpoints, to adequately train public officials who work in those facilities and in border areas to treat migrants respectfully and in accordance 15/19