A/HRC/42/CRP.1 449. With regard to the attack on the school bus in Sa’dah, it is striking that the JIAT considered the bus as a military objective despite the presence of so many children. Even if the principle of distinction was nonetheless respected, this strike raises serious concerns as to the principle of proportionality. There is also a violation of international humanitarian law in relation to precautions in attack, as acknowledged by the JIAT. 450. Based on the evidence available, the Group of Experts has reasonable grounds to believe that the coalition carried out airstrikes in the governorates of Sa’dah, Hajjah and Sana’a that may not have complied with the principles of distinction, proportionality and precautions in attack. Violations of the principles of distinction and proportionality amount to serious violations of international humanitarian law. Launching an indiscriminate attack resulting in death or injury to civilians, or launching an attack in the expectation that it will cause excessive incidental civilian loss, injury or damage may lead to individual criminal responsibility for war crimes.718 Further, the Group of Experts has reasonable grounds to believe that the specific protection of medical units has been violated by the coalition in the failure to take the necessary precautions to avoid damage to the Kitaf Hospital, and possibly in directing an attack at the MSF cholera treatment centre. Such attacks, particularly where directed at medical facilities, may lead to individual criminal responsibility for war crimes at all levels of command. 3. Hajjah governorate, the Hajour conflict, January to March 2019 (a) Context 451. Towards the end of 2018, the Stockholm Agreement, which included a cessation of hostilities in al-Hudaydah, was reached after international efforts focused on halting the military offensive there, as it potentially carried devastating consequences for Yemen’s scarce access to food and humanitarian supplies.719 At the same time, the complex dynamics of the conflict in Yemen resulted in the parties shifting their efforts to other areas. A new front emerged, this time in the far north, in the district of Hajour, in Hajjah Governorate. The conflict in Hajour, which took place mainly between January and March 2019, involved the Houthis and the tribes of Hajour, the latter of which were allegedly720 supported at points by al-Islah-affiliated and GPC-affiliated groups. Like many other localised conflicts across the country, this one also revived old and unresolved sectarian, tribal, and political grievances. Disputes between the Hajour tribes and the Houthis predate the conflict in Yemen and go back to the attempted takeover of Hajour by the Houthis in 2012 and 2013. Reported violent armed confrontations at that time ended with a truce between the two sides. The truce included, according to sources721, an agreement that the Houthis would not use the Hajour area for military purposes. 452. According to many sources, al-Islah party had a large base of support in that area, as did former President Ali Abdallah Saleh and the GPC which he led at the time. While the tribes of Hajjah and the Houthis had their share of sectarian disputes dating back to the eviction of the Salafist presence from Dammaj in January 2014, the alliance between former President Saleh and the Houthis in 2014 eased differences between them. The reemergence of disputes between Saleh and the Houthis, leading to his death in December 2017, marked the end of the entente. While the Houthis allege that the dispute with the Hajouri tribes was caused by the latter’s expansion and their setting up of checkpoints outside of Hajour, local sources allege that the Houthis started encircling the area towards the end of 2018, until they entered Hajour, breaking the six-year-old truce. Hajour is located at a strategic junction, connecting Sana’a to Sa’dah and leading to the coast from the western side of the governorate. Government of Yemen and coalition advances in Middi have placed more pressure on the Houthis in their northern “heartland”. The move into 718 See ICRC Study on customary IHL, rule 156. For further details on the battle of al-Hudaydah, see Chapter “Emblematic Situation: Battle of alHudaydah 2018-2019. 720 Maysaa Shuja Al-Deen, “The Houthi-Tribal Conflict in Yemen”, Carnegie Endowment for International Peace, 23 April 2019. 721 Confidential Sources on File. 719 112