BENI, Congo -- The head of United Nations peacekeeping operations vowed Wednesday to do more with Congo's government to help improve security in the country's east, where frequent attacks by rebels are undermining efforts to contain an Ebola outbreak that has killed more than 150 people.

Jean-Pierre Lacroix said the UN "will do our best to contain the Ebola outbreak despite the security environment that is being degraded by armed groups."

Lacroix singled out the Allied Democratic Forces rebels in particular. The group has killed more than 1,000 people in Beni and the surrounding region since October 2014.

"We promise to neutralize and hunt down these rebels because we have a mandate to keep the peace. Peace is one of the major elements of the Ebola response," Lacroix said.

The latest Ebola outbreak that was declared Aug. 1 is the first to occur in Congo's far northeast, where multiple rebel groups are active.

The ministry of health has said teams responding to the Ebola outbreak are attacked three or four times a week on average -- a level of violence unseen in the country's nine previous outbreaks of the virus.

World Health Organization's director-general Tedros Adhanom Ghebreyesus joined Lacroix in Beni as part of what he called joint UN efforts to stop Ebola.

The ministry on Tuesday said there are currently 305 confirmed and probable cases of the deadly virus in this latest outbreak in Congo -- among the largest Ebola outbreaks in the country in terms of numbers.

Tedros said the scale was not surprising, given the precarious security situation.

"We're using all we have at hand, of course it may take time. But from what we have seen today, and from all the activities we have, I believe that we can defeat Ebola," he said. "It's not about expanding the response. It's strengthening what we're doing, especially the community surveillance."

The fight is particularly challenging because of the region's high population density, high mobility and displacement, he added.