Attacks by gunmen linked to the Islamic State group have left at least 44 civilians dead in the northeastern Democratic Republic of Congo this week, humanitarian and security sources said on Friday.
The latest raids in the north-eastern Ituri province by the Allied Democratic Forces come just days after the notoriously brutal group killed 66 people in neighbouring North Kivu.
The province is a hotspot in the current outbreak of Ebola, and three health workers were among the dead while several medical facilities were burnt in that attack.
It prompted the World Health Organization's chief Tedros Adhanom Ghebreyesus to warn that the region's chronic instability represented "one of the greatest obstacles to the Ebola response".
This week's targets were roughly 100 kilometres away in villages in the Mambasa territory of Ituri where the deadly viral fever was first detected six months ago.
Formed from former Ugandan rebels, the ADF is infamous for extreme brutality towards civilians and has regularly carried out massacres in both North Kivu and Ituri.
"The ADF rebels are still in the bush and have set up ambushes," the humanitarian source said on condition of anonymity.
"Some bodies are already in a state of decomposition. The victims were hacked to death with machetes, while others were shot," said Gabriel Tonge, a local official.