Three experts working for the U.N.'s top human rights body say the governments of Yemen, the United Arab Emirates and Saudi Arabia may have been responsible for war crimes including deadly air strikes, rape, torture, disappearances and "deprivation of the right to life" during three and a half years of escalated fighting against rebels in Yemen.

In their first report for the Human Rights Council, the experts also point to possible crimes by rebel Shiite militia in Yemen, which has been fighting the Saudi-led coalition and Yemen's government since March 2015.

The experts have also chronicled the damages from coalition air strikes, the single most lethal force in the fighting, over the last year.

They urged the international community to "refrain from providing arms that could be used in the conflict "— an apparent reference to countries like the United States and Britain that help arm the Saudi-led coalition, as well as Iran, which the coalition has accused of say has been arming the Houthis.

The experts visited some but not all parts of Yemen as they compiled the report.

"(We have) reasonable grounds to believe that the governments of Yemen, the United Arab Emirates and Saudi Arabia are responsible for human rights violations," the report said. It cited violations including unlawful deprivation of the right to life, arbitrary detention, rape, torture, enforced disappearances and child recruitment.

It also accused the "de facto authorities" — an allusion to rebel leaders that control some of the country's most populated western and northern areas — of crimes including arbitrary detentions, torture and child recruitment.

The Associated Press reported last year that the UAE and its allied militias were running a network of secret detention facilities, beyond the control of the Yemeni government. In June, the AP revealed that hundreds of detainees had been subjected to sexual abuse and torture.

Yemen has been wracked by conflict since 2014, when Shiite Houthi rebels overran much of the country. Saudi Crown Prince Mohammed bin Salman, the former defense minister and its allies launched Operation Decisive Storm in March 2015. Riyadh accuses the rebel group of serving as a proxy force for Iran, Saudi Arabia's arch-foe in the region.

Since March last year, the U.N.'s humanitarian aid agency has called Yemen the world's worst humanitarian crisis — with three-fourths of its population of over 20 million in need of humanitarian assistance. The war has devastated the country's health system and provided the breeding grounds for the world's largest cholera outbreak last year.

The experts cited some 6,475 deaths from the conflict between March 2015 and June this year, but said the "real figure is likely to be significantly higher." Other groups have estimated that more than 10,000 people have been killed.

They also sharply criticized work by the coalition's Joint Incidents Assessment Team, which was set up as a bulwark against possible rights violations. They questioned the JIAT's explanations for the air strikes that have killed civilians, and challenged its "independence and its ability to carry out impartial investigations."

The experts also said nearly a dozen deadly airstrikes they investigated over the last year "raise serious questions about the targeting process applied by the coalition." They chastised some in-the-field coalition combatants for "routinely" failing to seek information about official "no-strike" lists that should have been avoided.

Even getting the experts up and running was an accomplishment for the U.N.-backed Human Rights Council, which passed a resolution creating the team last September. Largely due to the objections of Saudi Arabia and its allies, the council failed several times to authorize more intrusive investigation into possible war crimes in Yemen. The 47-member body only last fall reached a compromise to bring in the experts.

The report covers the period from September 2014 through June 2018, and does not address the latest series of deadly strikes that have killed dozens of children in rebel-held areas and sparked international outrage. The coalition has not confirmed or denied it carried out two air raids last Thursday that the U.N. said killed at least 26 children and four women south of the rebel-held city of Hodeida.

Those deaths came after a coalition attack on a bus in the northern rebel stronghold of Saada early this month killed 40 children, prompting U.N. Secretary-General Antonio Guterres to call for an independent investigation of attacks targeting civilians in the three-year war. In addition to becoming causalities of airstrikes, children have also suffered a far wider rage of consequences in the conflict.

"Children are the most vulnerable. Poverty, coupled with violence and insecurity render them defenseless and exposed to exploitation and abuse by parties to the conflict," Charles Garraway, a member of the expert group, told reporters.