The agency says that kidnapping of relief workers is a new element in eastern Chad, Darfur and northern Central African Republic.
Several humanitarian organizations have temporarily suspended or reduced their activities as a result of insecurity in the Assoungha and the Dar Sila regions.
OCHA warns that if this situation continues, nearly 100,000 people are at risk of losing essential aid.
According to OCHA, approximately 70 humanitarian organizations work in eastern Chad to help more than a quarter million Sudanese refugees and close to 170,000 internally displaced people in eastern Chad.
OCHA says the government of Chad and the UN mission in the Central African Republic and Chad have taken measures to better protect civilians and humanitarian workers, but that it's still not enough.
Bissera Kostova, United Nations
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