The United Nations' humanitarian coordinator in South Sudan yesterday called for the "swift and safe" return of six aid workers who have disappeared in the northwest of the country.
The co-ordinator, Alain Noudehou, said in a statement that one international and five national aid workers had gone missing on Sunday while travelling between the towns of Raga and Wau, where they were working on food security.
The six were employed by two foreign organisations, and one national organisation.
On Monday, France-based NGO Solidarites International said it had "lost contact" with three of its workers, but said it could not be confirmed whether they had been kidnapped.
The South Sudanese government, and rebels led by exiled former vice-president Riek Machar, accused each other of attacking the aid workers during clashes which broke out in the area.
The information ministry in the state of Lol, where Raga is situated, said in a statement that Machar's "bandits" had ambushed vehicles 30 kilometres (18 miles) outside of Raga, killing eight civilians and kidnapping four aid workers.
Meanwhile, Lam Paul Gabriel, a spokesman for the rebel SPLA-IO, said his forces had "intercepted" a convoy carrying weapons between the second largest city of Wau and Raga which were to be used to attack rebel bases.
He said that in the course of this operation, four aid workers were "rescued", adding they had been used as "being used as shields by the government in the transportation of these military hardwares."
"They are currently safe and sound with our forces around Raga and will be handed over to the concern third party as soon as possible," said the statement.
It could not be immediately confirmed if all six aid workers mentioned by the UN humanitarian co-ordinator went missing in the same incident.
Wau and its surrounds have been the centre of fierce fighting between the government and rebel forces since 2016.