The current Ebola epidemic in the Democratic Republic of Congo has killed nearly 1,000 people, the UN said Friday, warning the "intense" spread of the virus was set to persist.
The World Health Organization had initially voiced hope it would be able to contain the outbreak declared in August in eastern DRC, thanks in part to a new vaccine.
But in recent weeks senior WHO officials have conceded that insecurity in the restive region, scarce financial resources and manipulation of the Ebola issue by local politicians to turn people against health workers has seriously undermined the containment effort.
"We are dealing with a difficult and volatile situation," Michael Ryan, the executive director of WHO's Health Emergencies Programme, told reporters in Geneva.
"We are anticipating a scenario of continued, intense transmission," he added.
As of May 1, there have been 1,510 Ebola cases in North Kivu and Ituri provinces, with 994 deaths.
The death toll will "likely" pass 1,000 when WHO receives an update later Friday, Ryan said.
The long-standing presence of various rebel groups in Ituri and North Kivu has made it difficult for health workers to access those who might have come into contact with Ebola, a figure that currently stands at 12,000 people.
But beyond the militias, communities in the aftermath of DRC's December elections "are being manipulated" against cooperating with Ebola responders, Ryan said.
"Communities...need to be assured that all parties are supporting the public health response and that Ebola should not become further politicised in the process," he added.
Ryan said the UN health agency currently has enough vaccine stocks to meet its needs but doses may run short.
"We don't necessarily know which way this outbreak is going," he said.
The current Ebola outbreak is the tenth in DRC in 40 years.
It is already the second deadliest on record globally, after the epidemic that struck West Africa in 2014-2016 and killed more than 11,300 people.