A/HRC/42/17 the context of heavy and immediate fighting, while the forces were conducting an offensive. The incidents indicate that the forces used mortar shells on heavily populated areas as a tactic to help them to gain territory. In the other two incidents, the shelling took place across frontlines that were relatively calm at the time of the attacks, hitting heavily populated areas. 40. The Group of Experts also examined several shelling incidents in Ta’izz city allegedly by Yemeni armed forces and affiliated groups; the Group had not completed its investigations into the incidents at the time of finalizing the present report. 41. The Group of Experts found reasonable grounds to believe that the Yemeni armed forces and affiliated groups, including armed groups backed by the United Arab Emirates, were responsible for serious violations of international humanitarian law for having launched indiscriminate attacks due to the weapons used and the locations, regardless of whether there was a military objective in the area. These acts may lead to criminal responsibility for war crimes. (d) Shelling by undetermined perpetrators 42. On 2 August 2018, three mortars, allegedly fired by Yemeni armed forces and affiliated armed groups backed by the United Arab Emirates, hit a fish market in Al-Hawak district, Al-Hudaydah. They were followed by two mortars, which landed outside AlThawrah hospital, killing 41 individuals, mainly civilians (including six children and four women), and wounding 111 (including 19 children and three women). Reports indicated that the target might have been a nearby Houthi base; however, the use of weapons with such a large impact diameter in a civilian populated area amounts to an indiscriminate attack and constitutes a serious violation of international humanitarian law. Further investigations are required to determine which entity is responsible for the attack. 2. Use of landmines by the Houthis 43. The use of landmines, both anti-personnel and anti-vehicle, by the Houthis has resulted in significant harm to civilians. Reports indicate that hundreds of civilians have been killed and many more injured by the devices. The Secretary-General documented 728 child casualties alone (149 killed and 579 injured, mainly boys) from landmines between 2013 and 2018 (S/2019/453, para. 38). 44. In May 2019, the de facto authorities confirmed to the Group of Experts that the Houthis used anti-vehicle mines, but denied the use of anti-personnel mines, referring to their obligations under international humanitarian law, including the Anti-Personnel Mine Ban Convention ratified by Yemen. 45. The Group of Experts investigated reports of civilian casualties caused by antipersonnel and anti-vehicle landmines allegedly emplaced by Houthi fighters in Aden, AlHudaydah, Lahij and Ta’izz governorates, and examined further reports of civilian casualties from landmines in Abyan, al-Dhale’e, Al-Bayda, Al-Jawf, Hajjah, Ibb, Ma’rib, Sana’a, Sa’dah and Shabwah governorates. It confirmed civilian casualties from anti-personnel landmines verified as having been emplaced by Houthi fighters in incidents it investigated in Aden, Al-Hudaydah, Lahij and Ta’izz governorates. Civilians encountered the devices outside their homes, on their farms and grazing land, on village paths, near water facilities, and on roadsides. For example, in Ta’izz Governorate, in February 2019, a woman stepped on an anti-personnel landmine while collecting firewood, causing her to lose her leg and wounding another woman. The Group verified civilian casualties from Houthi anti-vehicle landmines in the same governorates. This included anti-vehicle mines emplaced on roads in areas under Houthi control and areas previously under their control. On 1 August 2018, in Al-Hudaydah, the Governorate most affected by landmines, Houthi fighters failed to warn of landmines on the road ahead, and a minibus transporting civilians hit an anti-vehicle landmine, killing a 14-year-old boy and injuring a 17-year-old boy. 46. The Group of Experts has reasonable grounds to believe that the Houthis used antipersonnel and anti-vehicle landmines, in violation of international humanitarian law, notably in the way the mines were emplaced in unmarked locations frequented by civilians, with little or no warning given, which rendered their use indiscriminate. The use of anti-personnel 8