Juba: Gunmen have seized a United Nations worker in war-torn South Sudan, the World Food Programme said on Friday in a plea for his release.
"We have not heard from our colleague for almost 24 hours, and we are extremely concerned about his well-being," WFP chief in South Sudan Eddie Rowe said in a statement.
"WFP demands that his captors release our staff member unharmed."
The UN worker, a South Sudanese national, was waiting in line for a flight from the northern town of Malakal on Thursday when he was "taken at gunpoint... by eight armed men wearing plain clothes," WFP added.
It was not clear if the gunmen were from the country`s feared national security, or from another group.
Aid workers have been targeted in the more than 10-month long civil war.
In August, gunmen killed at least six South Sudanese staff members of international aid agencies.
The town of Malakal has changed hands several times in the ongoing civil war, but is now in government control.
Thousands of people have been killed and almost two million have fled fighting between government troops, mutinous soldiers and ragtag militia forces divided along tribal lines.
"We are concerned..he was in a line waiting to board a flight, when people just came and took him into a vehicle," said Bennett Kenyi, the head of the association for local UN workers.