In January 2015, Houthi forces, also known as Ansar Allah, effectively ousted Yemeni President Abdu Rabu Mansour Hadi and his cabinet; he subsequently relocated to Saudi Arabia and re-established a government there.

In March, after Houthi and allied forces advanced south, threatening the port city of Aden, a Saudi Arabia-led coalition of Arab countries, with the participation of the United States, began a campaign of airstrikes against them. On March 26, coalition warplanes attacked Houthi forces in Sanaa, the capital, and other locations. The airstrikes continued throughout 2015 as fighting occurred across the country, with Bahrain, Sudan, Saudi Arabia, and the United Arab Emirates sending ground troops to battle Houthi and allied forces.

Dozens of coalition airstrikes were indiscriminate, violating the laws of war and killing and wounding thousands of civilians. The coalition also used cluster munitions, banned by international treaty. Houthi forces also committed serious laws-of-war violations by firing indiscriminate rockets into southern cities and Saudi Arabia, killing dozens of civilians.

They also laid banned antipersonnel mines in eastern and southern Yemen before withdrawing. Southern forces, supported by the Saudi-led coalition, also committed serious abuses, executing Houthi prisoners in Aden. None of the warring parties carried out meaningful investigations into their forces’ alleged violations.

Airstrikes

Human Rights Watch documented dozens of coalition airstrikes that appear to have been unlawfully indiscriminate, causing civilian casualties, some of which may have amounted to war crimes. They include a March 30 airstrike on a camp for internally displaced persons near Yemen's border with Saudi Arabia that killed at least 29 civilians; a March 31 airstrike on a dairy factory outside Hodaida that killed at least 31 civilians; a May 12 airstrike on a market and neighboring lemon grove in the town of Zabid, south of Hodaida, killing at least 60 civilians; a July 4, airstrike on a village market in Muthalith Ahim, south of the Saudi border, killing at least 65 people; and a July 24 airstrike on homes in the port city of Mokha that killed at least 65 civilians.

In the Houthi's northern stronghold of Saada, Human Rights Watch examined a dozen coalition airstrikes that destroyed or damaged homes, five markets, a school, and a gas station, but found no evidence of military targets. The strikes killed 59 people, all reportedly civilians, including at least 35 children, between April 6 and May 11.