A doctor in eastern Democratic Republic of Congo is hospitalised with Ebola, and 97 of his contacts have been identified in an area almost entirely surrounded by armed militia, the World Health Organization (WHO) said on Friday.

"It is the first time we have a confirmed case and contacts in an area of high insecurity. It is really the problem we were anticipating and at same time dreading," Dr. Peter Salama, WHO deputy director-general for emergency preparedness and response, told a news briefing.

The town of Oicha is almost entirely surrounded by ADF Ugandan Islamist militia, there are "extremely serious security concerns," he said, adding that the group held hostages.