Two aid workers were killed and one kidnapped over the weekend in the Democratic Republic of the Congo, the United Nations reported Monday.
The three humanitarian workers were from the French nongovernmental organization Hydraulique Sans Fronti-res.
Two aid workers killed, one kidnapped, in eastern DRC.
Humanitarian workers must never be targeted, UN says.
"The humanitarian country team condemns, with firmness, the latest attack that led to the tragic loss of colleagues engaged in emergency humanitarian assistance and calls for immediate and unconditional release of the person held hostage," said the UN's Office for the Coordination of Humanitarian Affairs, which is known as OCHA.
Hydraulique Sans Fronti-res is based in Chamb-ry, France, and supports technical projects in developing countries. The nongovernmental organization focuses on clean drinking water, irrigation, sanitation and electrical generation, its website says.
According to OCHA, the attack was carried out by unidentified armed men in the Rutshuru territory of North Kivu, an eastern province that borders Rwanda and Uganda. The area has been embroiled in violence since 1994, when Hutu forces crossed the border from Rwanda fearing reprisals after the genocide there.
"Security conditions are very worrying in North Kivu and represent a major obstacle for humanitarian organizations to access the thousands of people who are in need," OCHA added in its statement.
In December 2017, 15 UN peacekeepers were killed and 53 others injured in North Kivu in what the United Nations said constituted a war crime. UN Secretary-General Antonio Guterres called the attack, which was carried out by the rebel group Allied Democratic Forces, the worst offensive on peacekeepers in recent history.
The various armed conflicts and insecurity in the Democratic Republic of the Congo have created one of the "world's most complex and longstanding humanitarian crises," OCHA stated on its website. The Democratic Republic of the Congo, with a population of over 80 million, remains OCHA's largest operation in the world.
"This is an opportunity to make it clear that humanitarian workers must never be targeted," the OCHA statement added.