Several humanitarian workers have been killed in Ethiopia's Tigray region which has been experiencing fighting between a separatist group and government forces since early November.
In a statement on Friday, the Danish Refugee Council confirmed the deaths of three colleagues in Tigray last month.
"Sadly, due to the lack of communications and ongoing insecurity in the region, it has not yet been possible to reach their families. We will continue all efforts to reach them and ensure that they receive support," it added.
The International Rescue Committee (IRC) also confirmed the killing of a staff member in Hitsats Refugee Camp in Shire, Ethiopia.
"We call on all parties to the conflict to agree to an immediate ceasefire and ensure civilians, including refugees and aid workers, are protected and able to continue to access and deliver life saving services," IRC said.
Ethiopian authorities have not yet made any comment regarding the death of humanitarian workers in the region.
Ethiopia launched on Nov. 4 a "law enforcement operation" against the Tigray People's Liberation Front (TPLF) whose forces stormed an army camp, looted military hardware and killed soldiers.
Up to 50,000 Ethiopian refugees who have crossed into eastern Sudan, with some reporting having to evade armed groups to reach safety, according to the UN Refugee Agency.
On Wednesday, Michelle Bachelet, the UN High commissioner for human rights said the situation in Ethiopia is "exceedingly worrying, volatile, and distressing" with an urgent need for independent monitoring of the human rights situation in the conflict-stricken Tigray region.
Last week, Ethiopia's government said it had signed a humanitarian access deal with the UN to coordinate Tigray's essential supplies.
Prime Minister Abiy Ahmed declared the end of military operations in the region on Nov. 28 after the fall of the regional capital, Mekelle.