The Rapid Support Forces, which have been fighting Sudan's regular army since April 2023, captured the military's last stronghold in western Darfur in October after an 18-month siege.

Reports later emerged of mass killings, abductions, rape and widespread looting.

Last week, the UN's independent fact-finding mission on Sudan said the assault on El-Fasher bore "the hallmarks of genocide".

"Human Rights Watch has documented abuses against people with disabilities in armed conflict around the world for over a decade," said Emina Cerimovic, the group's associate disability rights director.

"But this is the first time we have documented this type and scale of targeted abuse."

HRW interviewed 22 survivors and witnesses from El-Fasher and found that RSF fighters singled out civilians with disabilities as they tried to flee.

"The Rapid Support Forces treated people with disabilities as suspects, burdens or expendable," Cerimovic said.

She added that fighters accused amputees of being injured soldiers and "summarily executed them", while others were mocked as "insane" or "not being a complete person".

A 29-year-old nurse said fighters executed a young man with Down syndrome whose sister had carried him on her back.

"After killing her brother, they tied her hands, covered her face and took her away," said the nurse.

The nurse also described fighters ordering a woman carrying a blind teenage boy on her back to put him down.

"She said 'he cannot see'," the nurse said. "They immediately shot him in the head."

Another witness said he saw fighters kill "more than 10 people", most with physical disabilities.

Others were beaten, detained for ransom or stripped of essential devices such as wheelchairs and hearing aids, leaving many unable to escape, HRW said.

Conditions in displacement camps also remain dire, with "bathrooms and other facilities... inaccessible" to people with disabilities, witnesses told HRW.

On Tuesday, the UN Security Council sanctioned four RSF commanders over atrocities in El-Fasher.

The wider conflict has killed tens of thousands of people, displaced 11 million and triggered one of the world's worst humanitarian crises.