The health ministry named the new patients as a Ugandan driver, a Ugandan health worker and a woman from the DRC. All are alive.
Ebola is a deadly viral disease that spreads through direct contact with bodily fluids. It can cause severe bleeding and organ failure.
The current epidemic centers on the conflict-wracked eastern DRC, where it was detected in Ituri province, which borders Uganda, before spreading to South Kivu.
The Red Cross said on Saturday that three Congolese volunteers had died in Ituri after apparently contracting Ebola there.
The three “were carrying out dead body management activities on March 27 as part of a humanitarian mission unrelated to Ebola,” said the International Federation of Red Cross and Red Crescent Societies.
“At the time of the intervention, the community was not aware of the Ebola virus disease outbreak... They are among the first known victims.”
Ebola has killed more than 15,000 people in Africa in the past half-century.
On Friday, the WHO raised the risk from Ebola in the DRC to its highest level — “very high.”