GENEVA (AP) — The World Health Organization says it is "deeply concerned" by the ongoing Ebola outbreak in Congo but the situation does not yet warrant being declared a global emergency.

After convening an expert group to assess the epidemic on Wednesday, the U.N. health agency says "response activities need to be intensified and ongoing vigilance is critical."

Aid organizations have expressed alarm as the rate of new Ebola cases more than doubled this month and resistance to efforts to stop the virus has turned violent. WHO has warned the risk of Ebola spreading in the region is "very high."

To warrant being declared a global emergency, an outbreak must be "an extraordinary event" that might cross borders, requiring a coordinated response.

Congo says there have been 181 confirmed cases, including 104 deaths.