The ongoing Ebola outbreak in Democratic Republic of Congo has spread to a new province bordering Central African Republic, two health officials said on Thursday, posing a fresh challenge for authorities struggling to contain it.

North Ubangi becomes the eighth province to be affected by the outbreak of the Bundibugyo species of Ebola, which was announced in mid-May and has become the second-largest Ebola outbreak on record, with more than 9 000 cases and more than 4 000 deaths confirmed. 

Two cases have been confirmed in North Ubangi, the officials said. They have not been officially announced by Congolese authorities.

Ituri province remains the epicentre of the outbreak though cases have increased recently in North Kivu province. Cases have also been confirmed in South Kivu, Tshopo, Haut-Uele, Bas-Uele and South Ubangi provinces. 

A health official in North Ubangi told Reuters on Thursday there had been a series of suspect deaths recently in a mining area in Wapinda health zone, close to the border with Bas-Uele, prompting samples to be analysed at a provincial laboratory and in Kinshasa.

In addition to spreading within Congo, the outbreak has also resulted in cases in Uganda, which was declared Ebola-free in August, and in Kenya, which announced its first Ebola infection earlier this month and announced a second case - a close family member of the first one - on Wednesday.