Ten aid workers have gone missing near the town of Yei in South Sudan.
The UN Office for the Co-ordination of Humanitarian Affairs (OCHA) says the group, made up of staff from different agencies, had been on its way to conduct an assessment of humanitarian needs.
The missing individuals are reported to be staff of the UN and other organisations.
A senior UN official in South Sudan Alain Noudehou said their whereabouts and condition were not known.
He demanded their immediate release – a suggestion that they’d been seized – but gave no indication of who would have been behind the disappearance.
Government forces and rebel factions are present around the region where the aid workers went missing – part of the fighting that has continued in South Sudan, despite several peace agreements.
This is the second incident of its kind in the country involving aid workers this month.