"Although we did not expect to face a tenth epidemic so early, the detection of the virus is an indicator of the proper functioning of the surveillance system", said the country's health minister, Oly Ilunga Kalenga, in a statement.
Rwanda is on a high alert following a fresh outbreak of the deadly Ebola disease in neighbouring Democratic Republic of Congo.
The majority of the cases are in the Mangina health area which is 30 kilometres from the city of Beni.
Officials said it was not yet clear whether the two Congo outbreaks separated by more than 2,500 kilometers (1,553 miles) are linked. Authorities do not believe the new outbreak is connected to the Bikoro outbreak, which infected 54 people and killed 33 and which was just declared over.
Dr Fatoumata Nafo-Traoré, IFRC's Regional Director for Africa, said: "We anticipate an extremely challenging operational environment, given the fact that the presumptive outbreak is occurring in an area affected by conflict, and that is close to both a major population centre and an worldwide border".
Congo's health ministry on Wednesday announced the four new Ebola cases in Mangina, adding that at least 20 people have died from a hemorrhagic fever. Six samples from these patients were tested, and four tested positive for Ebola, the ministry said.
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This latest outbreak is the 10th since the first one was discovered in 1976.
Global experts set up a laboratory today in Beni, WHO and Congolese officials said.
There is no specific treatment for Ebola, and the virus can be fatal in up to 90 percent of cases, depending on the strain.
Transmission among humans then typically spreads through close contact with the blood, body fluids, secretions or organs of someone who is sick with Ebola or has recently died.
In the worst outbreak of Ebola, the disease struck the West African states of Guinea, Liberia and Sierra Leone in 2013-15, killing more than 11,300 people.
He says it is crucial to gain access to the area as quickly as possible.He says having people and material in the country from the outbreak in Equateur is very helpful in tackling the outbreak.