The UN in South Sudan said Thursday a convoy including 10 aid workers had gone missing in the southwest of the war-torn country, presumed kidnapped.
The convoy disappeared after departing from the town of Yei, in Central Equatoria, early Wednesday heading for Tore, according to a statement issued by the UN Office for Coordination of Humanitarian Affairs (OCHA).
"We are deeply concerned about the whereabouts of these humanitarian workers and are urgently seeking information about their well-being," said Alain Noudehou, the UN's humanitarian chief in South Sudan.
Aid workers have frequently been targeted during South Sudan's four-year-old civil war.
The conflict has killed tens of thousands, forced millions from their homes and pushed millions more to the brink of starvation.
In its statement, OCHA said this was, "the second incident involving aid workers being held by armed groups in April alone, and the third in six months."
"These individuals, UN and NGO staff, are here to help the people of South Sudan and should not be targeted. Our colleagues must be released without condition so that their work can continue," he said.
The statement added that the 10 missing aid workers are all South Sudanese nationals.
They include staff working for OCHA and the UN's children's agency (Unicef) as well as the South Sudanese Development Organisation (SSDO), Christian aid group ACROSS, Plan International and Action Africa Help (AAH).