May 24 (UPI) — The International Federation Red Cross and Red Crescent Societies that three of its volunteers have died in the Democratic Republic of the Congo amid an Ebola virus outbreak.

The organization said the three volunteers working in the Mongbwalu branch in Djugu territory, Ituri province, were believed to have contracted Ebola while carrying out duties. Ituri province is the epicenter of the Ebola outbreak, which has killed a suspected 177 people in the DRC and Uganda.

The IFRC identified the three workers as Alikana Udumusi Agustin, who died May 16; Sezabo Katanabo, who died May 15; and Ajiko Chandiru Viviane, who died May 5.

“We extend our heartfelt condolences to their families, loved ones, fellow volunteers and colleagues,” the IFRC said in a statement Saturday. “We stand in solidarity with the DRC Red Cross during this difficult time.”

The IFRC said the three volunteers are believed to have contracted the Ebola virus while handling dead bodies on March 27, before the region was aware of the impending outbreak. The organization said the three were among the first victims of the outbreak.

During an update on Friday, the World Health Organization raised the risk of the Ebola outbreak in the DRC to “very high.” The international health organization, which is an arm of the United Nations, said the outbreak doesn’t meet the criteria of a pandemic, but the spread of the virus could be bigger than currently known.

This Ebola outbreak has been linked to the Bundibugyo virus, making it particularly challenging to treat. Unlike the Ebola-zaire strains of the virus, there are no approved approved therapeutics or vaccines for the Bundibugyo strain, the WHO said.