The WHO said 166 death has occurred which were linked to the disease since April.
Specialist laboratories in the U.S. and Gabon has confirmed the outbreak of the highly-contagious Ebola haemorrhagic fever, in the Western Kasai province, WHO said.
Another but less deadly disease have confirmed the presence of Shigella dysentery type 1 in the country.
"As of 11 September 2007, WHO is aware of 372 cases and 166 deaths associated with the ongoing event in the province. Additional samples have been taken for further laboratory analysis," the WHO said in a statement.
A WHO spokesman stressed out that Shigella infectious disease could be responsible for some of the deaths but five samples sent to one laboratory, all showed signs of Ebola virus.
Ebola virus symptoms include bleeding under the skin and in severe cases, from the mouth, ears, eyes and other body openings.
The virus, which has no known cure, is highly infectious for those who come into contact with a victim's body fluids.
Ebola had previously killed almost 450 people in the DRC since 1976, and about 1,200 people across the whole of Africa has been affected and died in the same period.
