The latest outbreak is in central Kasai province, with 28 suspected cases recorded, the ministry said.
Officials have urged strict adherence to preventive measures, including frequent handwashing and social distancing in high-risk areas.
Tests identified the Zaire strain of Ebola, a rare but often deadly disease, officials said.
The World Health Organization (WHO) said it was “acting with determination to rapidly halt the spread of the virus and protect communities”.
Four health workers were among the 15 people who had died, it said.
“Case numbers are likely to increase as the transmission is ongoing. Response teams and local teams will work to find the people who may be infected and need to receive care, to ensure everyone is protected as quickly as possible,” WHO added in a statement.
DR Congo had a “stockpile of treatments”, including 2,000 doses of the Ervebo vaccine, “effective to protect against this type of Ebola”, the global health body said.
The last Ebola outbreak in DR Congo was three years ago, killing six people.
An outbreak in 2018-20 was far deadlier, claiming more than 2,000 lives.
The virus, which is thought to have originated in fruit bats, was first detected in 1976 near the Ebola River in what is now DR Congo.
People are infected when they have direct contact through broken skin, or the mouth and nose, with the blood, vomit, faeces or bodily fluids of someone with Ebola.
