Around 250 people are suspected of being infected with the serious disease, the African Union's public health agency, Africa CDC, announced.
Several deaths have been confirmed in Ituri province. Regional health authorities have called an emergency meeting for Friday to coordinate measures.
The risk of infection is increasing due to population movements linked to the mining industry, as well as poor security in some areas, lack of contact tracing, and the proximity of affected regions to Uganda and South Sudan, according to the Africa CDC.
Ebola is a rare but often fatal hemorrhagic fever spread through bodily fluids.
