GENEVA — An outbreak of the Ebola virus in the Democratic Republic of Congo poses a high risk to the region, though the danger of the disease spreading worldwide was described as low, international health officials said on Friday.

More than 20 people are believed to have died in the latest outbreak, which the Congo government said on Wednesday had affected North Kivu Province, where conflict between armed groups has displaced more than a million people. North Kivu, in northeastern Congo, has borders with Rwanda and Uganda.

The outbreak is “at the top of the scale” in terms of the difficulty of responding, Dr. Peter Salama, head of the World Health Organization’s emergency response unit, told reporters in Geneva.

Suspected cases are under investigation across an area of more than 150 square miles, Dr. Salama added, citing the challenges of operating over large distances in a conflict zone.