More than 2,000 nomads in Ethiopia’s Somali region have died since 2014 after falling ill from a mysterious disease that caused bleeding from their mouths and noses.
Other reported symptoms include swollen limbs and green or yellow eyes.
The affected people roam with their cattle around the Ogaden Basin region, which is being explored by companies looking for oil and natural gas.
Reports of the mysterious illness and deaths have drawn Western reporters and researchers from rights groups to investigate.
Residents of Calub, Ethiopia, have accused a Chinese project that includes construction of a pipeline from Ogaden to Djibouti of destroying the environment where their animals are grazing.
Chinese firm Poly-GCL has been prospecting for natural oil and gas in Ogaden since 2014. It is expected to start commercial gas production soon. The Ethiopian government has signed a deal with the Chinese company that gives it 50% of any income from oil or gas exploration.
The pipeline will enable Ethiopia to export natural gas.
Local residents say they have not been consulted.
The government in Addis Ababa has denied allegations that the project is causing a health and environmental crisis in the region.
Prime Minister Abiy Ahmed has promoted oil and gas industry as essential for Ethiopia’s economic growth.