Of the five samples drawn, two tested positive for Ebola-Zaire.
The Health Ministry said Tuesday that five samples were taken from suspected cases in Bikoro in the northwest.
A team was sent by the World Health Organization and Doctors Without Borders over the weekend to investigate and strengthen coordination.
Since that time, no deaths have been reported among those hospitalised or among health workers treating the ill, it said.
A team of experts from the WHO, Doctors without Borders (DRC) and Equateur province travelled to Bikoro on Tuesday to beef up coordination and carry out investigations, it said. They will also look at the origin of the infection and how the outbreak began.
Two nurses who cared for him contracted Ebola, but recovered.
Since 1976, this is the ninth outbreak of Ebola in Congo. It was named after the Ebola river in the east of the country.
The latest cases come less than a year after the Congo's last confirmed Ebola outbreak in May 2017, during which eight people were infected, four of whom died.
Ebola, which has no proven cure, killed more than 11,300 people in West Africa from 2013-16 as it swept through Guinea, Sierra Leone, and Liberia.
Ebola occasionally jumps to humans from animals, including bats and monkeys.
Stopping the virus from spreading further is now the top priority of the WHO.
It often spreads to humans via infected bushmeat.
There are now no licensed treatments or vaccines for Ebola, although potential new therapies are now under development.
"Our country is facing another epidemic of the Ebola virus, which constitutes an global public health emergency", the ministry said in a statement.