12 people have been killed in clashes in the Democratic Republic of Congo's Butembo city, which is one of the places most affected by the Ebola epidemic.
The toll was confirmed by the mayor of Butembo city who said the 12 were mostly rebel fighters, and that they had been killed in clashes with the Mai Mai militia.
The DR Congo health ministry has issued an order suspending all the activities of Ebola response workers in the town until further notice.
The country has been dogged by an Ebola epidemic for years, thousands of people.
Since August last year, more than 1,000 have died from the disease.
Another attack in Butembo last month left one doctor dead and several people injured.
That attack was condemned by WHO Director-General Tedros Adhanom, who said the attacks were hampering efforts to tackle the spread of Ebola in the country.
WHO experts earlier this week recommende a dramatic expansion of vaccination against Ebola in the DR Congo after a surge in cases showed that the strategy of vaccinating those known to be exposed to the disease was no longer sufficient.
The agency recommended a number of changes, including expanding vaccination to a third ring of people exposed to those in the second ring, and “geographic” vaccinations that would target everyone at a location without trying to track their exposure.
(CGTN)