The last outbreak of this fatal virus in Congo was declared over just a week ago.
Travel into and out of the Mangina has been blocked.
World Health Organization says this new outbreak in North Kivu province is 2,500 kilometers away from Equateur Province, the site of the previous outbreak, and there is no link between the two.
The response to Congo's previous outbreak was considered a success despite the 33 deaths, as the use of a vaccine made by Merck helped contain the virus.
A team of 12 experts from Congo's health ministry will arrive in Beni on Thursday to set up a mobile lab, the ministry said.
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.
Health officials flew six blood samples to the capital of Kinshasa, where four tested positive for the Ebola virus.
Researchers have not yet identified the particular strain of ebola causing the new outbreak. "It is, on the other hand, worrying that this area is a conflict zone.It is an area with lots of displacement, so the access can be hampered in that way".
The Democratic Republic of the Congo has experienced nine outbreaks of the Ebola virus since 1976, when the nation was called Zaire. Once present in humans, it causes haemorrhagic fever, vomiting and diarrhoea and is spread through direct contact with body fluids.
An outbreak from 2014 to 2016 killed over 11,000 people in Sierra Leone, Liberia and Guinea.
Jose Barahona, Oxfam country director for the DRC, said the outbreak presented a serious risk to communities in Beni, where thousands of people are already facing hardship.