A/HRC/42/17 vulnerable displaced persons and marginalized Muhamasheen reside. From 2017 to 2019, members of the 35th Armoured Brigade kidnapped individuals and subjected them to rape, including gang rape, and other forms of sexual violence, including as a means to humiliate and subjugate members of these communities. 77. The aggressive behaviour of Security Belt Forces against migrants continued over the past year. From April to June 2019, Security Belt Forces detained more than 5,000 migrants in dire conditions in new makeshift facilities, on national security grounds. In 2018, the Group of Experts found widespread cases of rape of migrant women, girls and boys committed by Security Belt Forces at a previous facility in Aden, raising similar concerns for migrants at the new facility. 78. The Group of Experts investigated allegations of gender-based violence by members of the de facto authorities, including hostage-taking of women and girls. In 2018 and 2019, Houthi fighters in Sana’a and Al-Hudaydah kidnapped and detained women and girls for periods of up to eight months in order to blackmail relatives. In one case, they did so to force a Houthi defector to surrender; in others, they detained women and girls on the accusation of travelling without a male guardian, and held them for ransom. Kidnapping places the women and girls concerned at risk of sexual violence and attracts stigma in Yemen, placing them at further risk of gender-based violence. 79. The Group of Experts has reasonable grounds to believe that all parties to the conflict committed gender-based violence, including sexual violence, of persons in detention, and also that members of the Security Belt Forces backed by the United Arab Emirates and of the 35th Armoured Brigade of the Yemeni armed forces committed rape and other forms of sexual violence, and that members of the de facto authorities committed hostage-taking of women and girls. Perpetrators may be held responsible for war crimes, as such acts amount to serious violations of international humanitarian law. The Government of Yemen, the United Arab Emirates insofar as it is in control of areas and/or facilities, and the de facto authorities have also violated international human rights law, which prohibits rape and other forms of sexual violence, as well as hostage-taking. The Group continues to investigate further allegations of gender-based violence, noting that those presented as verified and described in the present report indicate broader patterns of such violence involving all parties to the conflict. F. Violations affecting children 80. Children in Yemen bear the wounds of the conflict, which continued to have a devastating impact on the realization of their fundamental rights. These include the rights to life, survival and development; protection from violence, injury and abuse, including sexual violence and forced marriage; liberty and security of person; the right not to be recruited into the armed forces or armed groups; and the rights to health, food and education. Furthermore, many of these violations also amount to violations of international humanitarian law, some of which may lead to criminal responsibility for war crimes. 81. Almost all cases of attacks involving civilians and indiscriminate attacks documented by the Group of Experts resulted in child casualties. The Secretary-General reported that, from 1 April 2013 to 31 December 2018, 2,776 children were killed in Yemen (1,940 boys, 787 girls and 49 children of unspecified sex) and 4,732 were injured (3,490 boys and 1,242 girls). Most of the child casualties were recorded between 2015 and 2018, with an increase in child casualties in 2018. The majority were attributed to the coalition, followed by the Houthis (S/2019/453, para. 33). 82. Following the coalition’s removal from the list of parties killing and maiming children in 2016, it claimed to have taken measures to improve the protection of children; nonetheless, children continued to be killed and injured by coalition airstrikes. For example, as detailed above, the Group of Experts verified that the coalition airstrike of 9 August 2018 on a bus in Sa’dah Governorate killed at least 11 boys aged between 10 and 15 and injured at least 12 others (United Nations and other reports indicated that as many as 39 boys had been killed). 83. According to the Secretary-General, of the 3,034 children recruited throughout the war in Yemen, 1,940 (64 per cent) were recruited by the Houthis (see(S/2019/453). The Group of Experts observed that Houthis pursued the practice of child recruitment, 14