A/HRC/30/31 documented. Even though appointed monitors could not always identify the group responsible for the recruitment of children, reports indicate that both government and nonState armed groups – including the Popular Committees and the tribal militias affiliated with the Islah party – are recruiting and using children as soldiers. 70. Under international law, the use and recruitment of children in armed conflict is strictly prohibited. The use of children below 15 years of age in active hostilities is a war crime. 71. OHCHR observed that, while the pattern of child marriage has been declining, it remains a common practice, affecting around 10 per cent of girls under the age of 15.16 Early marriage, a practice that contravenes international human rights law, is perpetuated by the lack of a legislative framework that identifies the minimum age of marriage and persisting traditions. Following advocacy efforts by UNICEF and OHCHR, language was included in the draft Constitution stipulating the minimum age for marriage as 18 years. F. Refugees, migrants, asylum seekers and internally displaced persons 72. During the period under review, large numbers of refugees, asylum seekers and migrants continued to arrive in Yemen. While a signatory to the Convention relating to the Status of Refugees, Yemen has not incorporated the Convention into national law nor has it established a procedure for determining refugee status. In the absence of such legislation, the legal status of asylum seekers and refugees has been governed by a combination of decrees and provisions. While the authorities may grant refugee status on a prima facie basis to Somali refugees, the Office of the United Nations High Commissioner for Refugees (UNHCR) determines refugee status for all other asylum seekers. 73. The scale and intensity of the conflict has left thousands of undocumented migrants trapped and deprived of basic resources and attention. According to UNHCR and the International Organization for Migration, more than 4,000 migrants arrived from the Horn of Africa in April 2015 alone. 74. On 20 April 2015, the Protection Cluster formed a task force on population movements to better coordinate partners’ efforts in collecting and disseminating consistent and reliable data on internally displaced persons in Yemen. Since the beginning of the aerial bombardment by coalition forces on 26 March 2015, the total number of displaced persons has increased to approximately 1 million.17 Furthermore, during the period under review, documented incidents of administrative detention of newly arrived immigrants appear to have increased. OHCHR understands that a large proportion of those detained are being held in overcrowded facilities. 75. During the period under review, hundreds of men, women and children continued to be victims of human trafficking into and from Yemen. OHCHR discovered numerous cases of displaced persons, including children, reportedly kidnapped in camps and subsequently trafficked abroad. Refugee women and children are at particular risk, and are often kidnapped for ransom. Cases of physical and sexual violence against men and boys were also reportede along the coast of the Red Sea. Smuggling and trafficking gangs have been reportedly operating with impunity in Yemen. 76. Progress was recorded in the Government’s efforts to set up institutional mechanisms to counter human trafficking. Established in 2013, the National Technical 16 17 14 UNICEF, Situation Analysis of Children in Yemen 2014. 2015 Yemen Humanitarian Needs Overview, 23 June 2015.