An Ebola outbreak in eastern Democratic Republic of Congo is likely spread and poses a high regional risk, given its proximity to borders, a World Health Organization (WHO) official said on Thursday.

Four people have tested positive for Ebola in and around Mangina, a town of about 60,000 people in North Kivu province, 100 km (62 miles) from the Ugandan border, the health ministry said. Another 20 people died from unidentified hemorrhagic fevers in the area, mostly in the second half of July.

News of the outbreak emerged just days after a previous outbreak on the other side of the Central African country that killed 33 people was declared over.