A/HRC/45/CRP.7 seven others. The circumstances of these incidents warrant further investigation against the background of the pattern of violations revealed in the Group’s investigations of coalition airstrikes over the last three years. Legal findings 74. In the four airstrikes or series of airstrikes it examined, the Group of Experts concluded that the coalition may have failed to take all legally necessary measures to minimise civilian casualties, namely in fulfilling duties to verify a target as a legitimate military target, to collect and assess intelligence relating to likely civilian impact, to cancel or suspend an attack if it becomes apparent that the target is not a lawful one, and to give an effective advance warning if circumstances permit, or if it would be a disproportionate attack (that is, an attack that could be anticipated to cause incidental loss of civilian life, injury to civilians or damage to civilian objects excessive in relation to the concrete and direct military advantage anticipated). Even if it were confirmed that the coalition were directing attacks against legitimate military targets in some of these airstrikes, the extent of civilian casualties that could have been anticipated raises significant questions as to the proportionality of the attacks and whether sufficient precautions in attack were taken. 2. Mortar/Rocket Shelling Factual findings 75. The Group of Experts is concerned at the continued practice by parties to the conflict of using indirect-fire weapon systems with wide-area impact, such as rockets and mortars, especially in populated areas. Given the imprecision of such weaponry, their usage in such environments gives rise to the likelihood of significant civilian casualties and damage to civilian buildings in excess of any anticipated military advantage, and increases the risks of misdirected attacks. 76. In one case investigated by the Group of Experts, for example, four boys were injured, including two severely, when a ground-fired munition (likely a mortar) exploded nearby as they played outside on the morning of 26 June 2019 in the village of Ghoal Al-Deymah, located approximately 1 km from a frontline, in Qa’atabah district, Al-Dhale’e Governorate. The munition was allegedly fired from Husn Al-Aql, a plateau 800m north of the village under Houthi control. 77. On 5 April 2020, at approximately 4.30 pm, several mortar rounds were fired by the Houthis towards the area of the Central Prison (Central Rehabilitation Facility) in the northwest of Ta‘izz city. One round killed 6 women - 5 inmates and 1 guard – as well as two young girls who were visiting their mothers in the female section of the prison, and injured 6 other female inmates. A man who was inside his vehicle was injured by another round that landed outside the prison on the road. Earlier on the day of the attack, discussions had taken place at the prison to finalise the release the next day of over 100 prisoners, including some of the women who were killed and injured, as part of efforts by the judiciary and lawyers to ease the prison population amid concerns over COVID-19. 78. The prison is located in the middle of a residential area, some 250-300 metres from what is commonly known as the “social welfare compound”. The 17th Brigade of the Ta‘izz Axis Command of the Government of Yemen had been using the buildings in this area as administrative headquarters. In January 2020, the National Commission for the Investigation into Human Rights Violations (also known as the National Commission of Inquiry to investigate allegations of violations and abuses committed by all parties to the conflict in Yemen, (NCOI) wrote to the Ta‘izz Axis Command requesting them to leave the buildings so they could be returned to the Office of Social Affairs and Labour and their original use. The Group understands this did not occur. The Group also received reports that the compound may have housed military equipment such as an armoured vehicle or tank. It is not known if the “social welfare compound” was the objective of this attack. However, even if a legitimate military objective were involved, the attack appears to have been carried out in an indiscriminate fashion. Witnesses interviewed by the Group reported that the general area had been shelled several times prior to that incident and throughout the conflict. 26