According to the health ministry, the latest outbreak has already claimed the lives of 20 people, including two health workers and comes only nine days after an outbreak in the western part of the country, in Equateur province, was officially declared over.
Another 20 people died from unidentified haemorrhagic fevers in the area, mostly in the second half of July.
The health ministry said four people have tested positive for Ebola in and around Mangina, a town of about 60,000 people in North Kivu province, 100 km from the Ugandan border.
UNICEF Spokesperson Christophe Boulierac said the local office had dispatched five specialists from the Ebola response team and are expected to dispatch more.
The outbreak on the western side of the country in June, infected dozens, and led to 33 deaths, but despite several cases appearing in a major city on the Congo River, it was fully contained after a massive global and national response.
"It would appear that the risk, as we can surmise for DRC, is high. For the region it's high given the proximity to borders, particularly Uganda", said WHO's emergency response chief Peter Salama.
Rwanda is on a high alert following a fresh outbreak of the deadly Ebola disease in neighbouring Democratic Republic of Congo.
These symptoms may be followed by diarrhoea, vomiting, troubles of the kidney and liver.
Ebola is a virus-caused hemorrhagic fever that in extreme cases causes fatal bleeding from internal organs, the mouth, eyes or ears. "This may involve the quick delivery of support, clean water and information, as well as assisting with the safe and dignified burials of people who have died which is critical for containing the spread of the virus".
The response to this was considered a success despite the deaths, as the use of a vaccine made by Merck helped contain the virus.
If it is the Zaire strain, the Merck vaccine used in the last outbreak may be an option, otherwise the situation will be much more complex "and we may not have any vaccine options", he told Reuters at WHO's headquarters in Geneva.
Salama said the "signal event" in this new outbreak was the death of a 65-year-old woman who had been admitted to the hospital in Mangina.