The United Nations has deployed peacekeeping reinforcements in Pibor in the troubled Jonglei state over the past four days as a column of 6,000 armed youths from the Lou Nuer tribe marched on the town in pursuit of members of a rival tribe, a senior UN official said Sunday.
"It appears that the column is now moving away from the town but the situation is very fluid," Lise Grande, the UN humanitarian coordinator for South Sudan, told AFP. "We remain on high alert and are very concerned that civilians may be at risk," she said.
The Lou Nuer youths, several hundred of whom had arrived on the outskirts of Pibor on Friday, were pursuing members of the Murle tribe who began fleeing towards Pibor several days ago after the Lou Nuer raided the town of Lukangol.
A group calling itself the Nuer Youth White Army issued a statement on 26 December vowing to "wipe out the entire Murle tribe... as the only solution to guarantee long-term security of Nuer cattle."
The group accuses the Murle of raiding Nuer cattle and killing members of their tribe since 2005, when a peace agreement ended two decades of civil war and led to South Sudan's independence this year.
Neither the UN nor South Sudan's former rebel army the SPLA have protected the Nuer, the group claimed.
"We the Nuer Youth have decided to fight the Murle, SPLA and the UN," it said.