Aid group Doctors Without Borders suspended its work in the Democratic Republic of Congo following two separate attacks on its Ebola treatment centers there.
"When I send my teams I need to be sure that they are going to come back alive," said Emmanuelle Massart, the on-the-ground emergency coordinator for Doctors Without Borders in the region.
"The attacks were really, really violent."
In the first attack, up to 100 men converged on a treatment center in a rural suburb of Katwa.
They started by throwing stones and then set fire the centre and some cars.
Just days later, another attack took place at another nearby treatment center in the city of Butembo. In that attacks, a car was used to ram the centre's gate and the attackers started shooting guns.
When police arrived, the attackers fired at them in a half-hour gun battle in which one police officer was killed.
Patients being treated fled the centre, with some remaining at large and infected by the deadly disease.
