He said 119 attacks have been recorded since January, 42 of them directed at health facilities, while 85 health workers have been wounded or killed.
World Health Organization has said the most recent Ebola outbreak remained contained to eastern Congo even as the number of cases rises in a dense, highly mobile population near the border with Uganda and Rwanda.
World Health Organization staff anticipated "continued intense transmission", he added, in a briefing to reporters in Geneva.
Rachel Kahindo, Ebola survivor working as a caregiver to babies who are confirmed Ebola cases, holds an infant outside the red zone at the Ebola treatment centre in Butembo, Democratic Republic of Congo, March 25, 2019.More news: Popular Australian DJ dies in accident on Bali holiday
More than 1 000 people have died from Ebola in the latest outbreak in Congo, the country's health ministry said Friday.
"Every time we have managed to regain control over the virus and contain its spread, we have suffered major, major security events", Ryan said.
Out of the 1510 cases registered in North Kivu and Ituri provinces of the country, as many as 400 have recovered, reported CNN. The vaccine is experimental, but is estimated to be 97.5 percent effective.
Doctors Without Borders and the International Rescue Committee suspend operations in the towns of Butembo and Kutwa.More news: Brazil's far-right president nixes USA trip in face of protests
"Since October 2018 the number of safe and dignified burials requested from communities has tripled, and this kind of work needs to continue if we are going to beat this disease", said Nicole Fassina.
Ebola virus disease (EVD) response activities in Butembo and Katwa remained limited; however, these are gradually resuming following a comprehensive reinforcement of security measures and community engagement efforts. More than 36 percent believed the epidemic was fabricated to destabilise the area.
"But the attacks on the Ebola treatment centres are more coordinated, by some kind of organised armed groups", she added.
The outbreak that was declared in eastern Congo in August is already the second deadliest in history, and efforts to control it have been complicated by attacks on hospitals and Ebola treatment centers and deep community mistrust.More news: Kim Jong Un Oversees North Korea Missile Firing Drills