Civilians account for half of the 6,600 deaths recorded since March 2015 in the impoverished country as Shiite Huthi rebels battle Yemen's internationally-recognised government backed by a Saudi-led coalition.
A UN casualty toll released on Tuesday identified 3,799 civilian deaths and 6,711 wounded.
President Abedrabbo Mansour Hadi's government is battling the Iran-backed Huthi rebels and allied forces who have seized control of large parts of Yemen since 2014 and still hold swathes of territory including the capital Sanaa
The following is a list of alleged violations and incidents likely to be probed by an independent, international investigation:
- On August 15, a coalition air strike killed 19 people at a hospital in northern Yemen that is aided by the French charity Doctors Without Borders (MSF). It was the fourth strike on an MSF-backed site in a year, the group says, and raised concern in Washington, which supports the coalition.
The coalition, which says it does not deliberately target civilians, vowed to conduct an internal investigation, as UN chief Ban Ki-moon stressed that attacks on hospitals, medical personnel or civilians were "a serious violation of international humanitarian law".
Signup to our newsletter and follow us on Facebook and Twitter!
- On August 4, the coalition acknowledged "shortcomings" in two out of eight cases it had investigated of air strikes on civilian targets. They took place in 2015 and involved a residential complex in Mokha, where 65 people died according to Human Rights Watch (HRW).
- On August 5, a provincial official said coalition air strikes killed six people while targeting a house in Huta, capital of Lahj province in the south, although UN staff also accused Huthi rebels of using civilians as human shields.
- In June, the UN placed the coalition on a list of governments and entities that do not respect children's rights, after a report concluded the coalition was responsible for 60 percent of the 785 children killed in Yemen in 2015.
Riyadh subsequently forced the UN to back down, but Ban on August 2 reaffirmed that "the content of the report stands".
- In late January, UN experts identified 119 air strikes that violated humanitarian law. They also said they had "troubling reports" of coalition planes dropping cluster bombs on residential areas of Sanaa. The coalition denied using the munition.
The Yemeni government temporarily expelled the UN human rights representative in the country following a report that the coalition had dropped cluster bombs in Hajjah province.
The UN High Commissioner for Human Rights said in early January that its staff in Yemen had found remnants of 29 cluster bombs during a field visit to Haradh district in the northwest.
In June, Amnesty and HRW called for Riyadh to be suspended from the UN human rights council, alleging Riyadh used its post on the panel to obstruct any probe of possible war crimes in Yemen.