GOMA, Congo (Reuters) - At least seven U.N. peacekeepers were killed in clashes with militias in an area that is at the center of the Democratic Republic of Congo’s worst Ebola epidemic, United Nations and diplomatic sources said on Thursday.

“Our peacekeeping colleagues tell us that six peacekeepers from Malawi and one from Tanzania who are part of the U.N. peacekeeping operation in the DRC ... were killed yesterday, in Beni territory, in North Kivu,” U.N. spokesman Stephane Dujarric told reporters in New York.

Eastern Congo has been plagued by banditry and armed insurrections for more than two decades since the fall of military ruler Mobutu Sese Seko, but the past year has seen a surge in violence around North Kivu.

Beni and the surrounding villages are also suffering an Ebola epidemic that has infected over 300 people and killed two-thirds of them.

This makes it the third worst outbreak ever, after a 2013-2016 outbreak in West Africa, when 28,000 people were infected, and in Uganda in 2000, when there were 425 cases.

Repeated armed attacks by at least two rebel groups are hampering international efforts to contain the virus, by preventing medical workers getting to Ebola victims.

A U.N. spokesman said that Secretary General Antonio Guterres “calls on all armed groups to stop their destabilizing activities, which continue to add to the suffering of the population and complicate the response to the ongoing Ebola outbreak”.