The Peace Corps announced Wednesday that it’s pulling volunteers out of parts of West Africa amid an outbreak of the deadly Ebola virus. Volunteers in Liberia, Sierra Leone and Guinea are being recalled until further notice.

“The Peace Corps has enjoyed long partnerships with the government and people of Liberia, Sierra Leone, and Guinea and is committed to continuing volunteers’ work there,” the group’s statement reads. “A determination on when volunteers can return will be made at a later date.”

The organization currently has 102 volunteers in Guinea, 108 in Liberia and 130 in Sierra Leone, it says. On Wednesday, CBS News reported two Peace Corps volunteers in Liberia had been quarantined after possibly being exposed to the deadly virus, though neither currently exhibits symptoms.

As of July 23, 672 people have died from Ebola during the current outbreak, which has spread between Guinea, Sierra Leone, Liberia and other parts of West Africa. Earlier this week, a hospital in Nigeria shuttered its doors after admitting a man who had contracted and later died from the virus.

World leaders are on high alert in light of the outbreak, which is the largest in history. Symptoms of Ebola include fever, diarrhea, vomiting and intense weakness; the fatality rate of this epidemic is about 60%.

Contact us at letters@time.com.