"All of us at UNICEF are shocked by the senseless killing of staff belonging to our partner organization, the Grassroots Empowerment and Development Organization. The humanitarian workers were travelling in a car that was clearly marked as belonging to a nongovernmental organization.
"We are appalled that humanitarians working to improve the lives of the vulnerable in South Sudan were so brutally targeted and call on the authorities to find and hold accountable those responsible.
"GREDO is working on community-based reintegration programmes, supporting children released from armed forces and groups.
"We offer our deepest condolences to the families and colleagues of the victims."