Doctors Without Borders announced - on Friday - the killing of 3 of its employees working in the Ethiopian province of Tigray, and said that their bodies were found meters from their car.
The organization added - in a statement posted on its website - that its branch in Spain had lost contact with its three employees - a Spaniard and an Ethiopian - for hours before the bodies were found with their car empty of any contents, and the circumstances of the accident are not yet clear.
The organization expressed its sadness and shock over the incident, and confirmed that what happened was a "horrific attack."
In this context, the US State Department - in a statement - expressed deep sadness over the killing of the three employees, and stressed the need to stop attacks on humanitarian workers there.
The statement called for an independent investigation and for the perpetrators to be held accountable for the killings, holding the Ethiopian government fully responsible for ensuring the safety of humanitarian workers and access to aid.
For its part, the European Union condemned the killing of MSF staff in the region and renewed its call for an immediate ceasefire.
The Ethiopian Ministry of Foreign Affairs had said that 3 Doctors Without Borders staff were killed in the "Abay Uday" area in the northern region of the country, and the ministry offered its condolences via Twitter, but stressed the need for military escorts for those traveling through the areas controlled by the Tigray Front.
The three are among at least 12 aid workers killed since fighting broke out in November between the Ethiopian army and forces loyal to the former ruling party, the Tigray People's Liberation Front.