Aftermath of a Saudi airstrike on Yemen's capital Sana'a on Wednesday (Khaled Abdullah/Reuters)Human Rights Watch has said that the Saudi-led coalition is using cluster bombs in its aerial intervention in Yemen's civil war. HRW said the cluster munitions were dropped on Yemen's capital Sana'a, controlled by the Ansar Allah (Houthi) movement, on Wednesday. Houses, a school, and vehicles were covered in pockmarks characteristic of the damage from cluster bombs. Human Rights Watch said photographs "showed unmistakable remnants of cluster munitions, including unexploded sub-munitions, spherical fragmentation liners from sub-munitions that broke apart on impact, and parts of the bomb that carried the payload". HRW has documented the use by coalition forces of three types of cluster munitions in Yemen, while Amnesty International documented a fourth type.