UNICEF says disease spreading fast, with number of suspected cases expected to reach 130,000 within the next two weeks.
An investigation – published on Friday by The Daily Beast website and funded by the Bureau of Investigative Journalism – said uniformed men belonging to a militia called the Elite Forces, which is controlled by the UAE, abducted men from their homes and brought them to a secret prison compound in southern Yemen, where they were allegedly tortured.
UAE forces have been fighting in Yemen since 2015 alongside members of a US-backed, Saudi-led coalition battling Houthi fighters and al-Qaeda-affiliated armed groups.
The investigation echoes a similar report put out by the United Nations earlier this year that warned of increasing instances of forced disappearances in UAE-controlled southeastern Yemen.
According to the UN, the UAE-backed Elite Forces were created to counter the rise of al-Qaeda fighters in the southeastern port city of Mukalla once the government regained control of the area in April 2016.
The city had previously been under the control of armed groups for nearly a year.
Efforts to take back the city were led by the UAE, which maintains a strong presence across the city.
Weeks of interviews with family members of the disappeared led the Bureau of Investigative Journalism to conclude the mass kidnappings were part of a campaign by the Elite Forces against al-Qaeda suspects.
Activists told the Bureau many of those abducted worked normal jobs while al-Qaeda was in control of the city, but had no connections to the group.