Eighty percent of new Ebola cases in eastern Democratic Republic of Congo are emerging from unknown chains of transmission, the World Health Organisation (WHO) said Tuesday, a sign the outbreak is spreading faster than health officials can track despite an expanding response.

Congo has been battling an outbreak of a rare type of Ebola since May, with no approved treatment or vaccine. The Africa Centres for Disease Control said it is the fastest-growing Ebola outbreak on the continent.

The number of confirmed Ebola cases in Congo has increased ‌to 2,011, ⁠including ‌754 deaths, ⁠government ​data ⁠showed on ⁠Tuesday.

The country's ⁠public health institute said ⁠in ​its ⁠latest report that 54 new cases were ​detected on ‌Monday in ​Ituri, North Kivu ​and Haut-Uele ⁠provinces.