Yemen's civil war has exacted an enormous toll on people with disabilities, who find themselves on the margins of society and excluded from badly needed humanitarian assistance, Amnesty International said in a report released Tuesday.

The 50-page report by the London-based global rights group shines a light on the inadequate or nonexistent support for disabled Yemenis — a population "most at risk and most marginalized" in the world's worst humanitarian crisis.

"We understand of course the extent of which the humanitarian response in Yemen has been overstretched," said Rawya Rageh, Senior Crisis Advisor at Amnesty International. "But this is not just about access to funds. What we are calling for is a change in perspective, a change in approach, that the rights of people with disabilities are addressed at the outset of the crisis."

In a war that has killed over 100,000 people, the number of wounded and disabled Yemenis is soaring as well, overwhelming health care facilities. Although verifying data is extremely difficult in the country, the World Health Organization estimates at least 4.5 million Yemenis suffer from disabilities, or 15% of the population.

The Amnesty report, citing nearly a hundred interviews with disabled people, government officials and aid workers, catalogues a daunting range of challenges that force disabled Yemenis to resort to desperate measures to survive.

The research focuses on government-controlled areas in the country's south, as the Iran-allied Houthi rebels, who seized northern Yemen in 2014 and have been fighting the Saudi-led coalition, which backs Yemen's internationally recognized government, for control of the country, refused to grant the group access.

Not only do disabled people live in a society that treats them as outcasts, Amnesty said, citing numerous cases of discrimination, but overburdened humanitarian organizations exclude them from proper access to aid.

Refugee camps lack accessible toilets, let alone wheelchairs, canes or devices like prosthetic limbs, confining disabled people to tents. Handicapped people described crawling to toilets and making laborious treks to faraway food distribution centers.

Yemen's war has also disrupted official sources of support for those with disabilities, Amnesty said, leaving many without monthly stipends for medical expenses. Without government help, a 14-year-old boy with cerebral palsy, for instance, has had to stop treatment, worsening his condition, according to Amnesty.

Furthermore, sudden outbreaks of violence have trapped disabled people and separated them from their families, Amnesty found. Many disabled Yemenis are forced to flee their homes without wheelchairs or crutches, carried in the arms of relatives.

Jalila al-Saleh Ali recounted to Amnesty how she abandoned her mentally ill husband at home while sprinting away from gunfire in the city of Taiz, holding her 16-year-old handicapped son.

As the war in the Arab world's poorest country grinds on, international donors must "do better to ensure these barriers that people with disabilities are facing are eliminated," urged Rageh. "People with disabilities cannot continue to be left behind."