A group of Americans in the Democratic Republic of Congo may have been exposed to the deadly Ebola outbreak in the country—including one with symptoms—which has triggered a WHO public health emergency declaration, reports said on Monday, as U.S. authorities work on a safe evacuation plan.

Staff members at CBCA Virunga Hospital prepare rooms intended for possible suspected Ebola cases following official announcements in Goma.

Citing unnamed sources, Stat News first reported that a “number of Americans” may have been exposed, including some who purportedly had “high-risk exposures.”

At least one American has developed symptoms, but there are no confirmed test results for any of them, the report added.

The Washington Post confirmed the report, noting that the person with symptoms may require a medical evacuation.