At least three WHO health workers have been killed and several more injured after two Ebola response centres in eastern Congo came under attack on Thursday.
Local militia, known as Mai Mai, also simultaneously attacked Ebola centres in Mangina in North Kivu and Byakoto in Ituri.
"It is a blow to the Ebola response because we were eradicating the disease. These attacks are challenging the efforts to date," said Jean-Jacques Muyembe, head of the Ebola response for the Democratic Republic of Congo.
The Mai Mai claim Ebola does not exist, and believe the response is a plot to eliminate the local population.
The second Ebola epidemic has left 2,199 people dead since the outbreak was announced in August 2018.
Israel's Netanyahu orders 'powerful attacks' in Gaza
At least 20 dead in operation against organized crime in Brazil's Rio
Hurricane Melissa to bring 'catastrophic situation' to Jamaica in storm of the century
Zelenskyy says Kyiv ready for peace talks, but will not cede territory
