Congo, with nearly 50 known cases across a large region bordering the Republic of Congo and Central African Republic.
Since authorities announced the outbreak on June 1st, 48 cases have been confirmed in Congo’s Equateur province, with a further three probable cases and a total of 20 deaths.
“This is still a very active outbreak, and I would say it is still a great concern,” Ryan told a news briefing.
The province includes part of the River Congo, he said, adding that it was a large geographical area where communities were linked and people travelled long distances.
There was previously a separate outbreak of Ebola in Ituri and North Kivu provinces of eastern Congo that was declared over last month.
That epidemic, the second largest on record, saw 3 463 confirmed and probable cases and 2 277 deaths over two years.