On March 26, 2015, a coalition of Arab countries led by Saudi Arabia, with United States participation, began a military campaign in Yemen that has so far resulted in the deaths of more than 2,500 civilians, mostly by coalition airstrikes. This report documents 10 coalition airstrikes from April through August that appear to have violated international humanitarian law, the laws of war.

The laws of war are intended to minimise harm to civilians and other non-combatants during armed conflict. While not all civilian casualties indicate laws-of-war violations, attacks that deliberately target civilians, that do not discriminate between civilians and combatants, or that cause disproportionate loss of civilian life or property, are all unlawful. Individuals who commit such violations with criminal intent are responsible for war crimes.

In the cases discussed in this report, which caused at least 309 civilian deaths and wounded at least 414 civilians, Human Rights Watch found either no evident military target or that the attack failed to distinguish civilians from military objectives. Under international law, states have an obligation to investigate alleged violations of the laws of war, and appropriately punish those individuals responsible for war crimes. Human Rights Watch is unaware of any investigations by Saudi Arabia or other coalition members in these or other reported cases.