The deputy governor of Warrap state, Sabino Makana, told Reuters that Nuer tribesmen killed 139 people and wounded 54 while seizing about 5,000 animals.
Mr. Makana added that he did not know if any Nuer was killed or wounded in the raid.
A local source told SCR News over the phone that the attack took place in a remote are in Tonj East, far from Tonj town, and people speak of over 100 victims.
Office for the Coordination of Humanitarian Affairs in south Sudan, Lise Grande, told Reuters the UN was sending a team to the Tonj area to check on the reports.