"Our country is facing another epidemic of the Ebola virus, which constitutes an international public health emergency," the Democratic Republic of the Congo's health ministry said in a statement.
The ministry says that of the five samples sent to the National Institute of Biological Research in Kinshasa, two came back positive for the Zaire strain of Ebola in the country's Equateur province.
Before the confirmation of the outbreak, local health officials reported 21 patients with signs of hemorrhagic fever. Seventeen of them died. It is not immediately clear whether some or all of the initial victims died from Ebola.
"Since notification of the cases on 3 May, no deaths have been reported either among the [hospitalized] cases or the healthcare personnel," the Health Ministry statement said.
On May 3, medical teams from the World Health Organization and Doctors Without Borders collected five samples from active cases in the area, two of which tested positive for Ebola, according to the WHO and the Congolese government.
In 2014, Ebola epidemic hit West Africa infecting some 28,600 and killing more than 11,300 before WHO declared the region Ebola-free two years later. The epidemic was concentrated in Liberia, Guinea and Sierra Leone.
Since then, a vaccine called rVSV-ZEBOV has been developed to prevent the spread of the disease, which has a particularly high mortality rate.
In the past few years, there have been isolated outbreaks, including one in Congo last year that infected eight, killing four of them.
The Nigeria Immigration Service (NIS) has resumed airport temperature screening at its international airports to ensure that Ebola is not brought into the country by infected persons.