The police in South Sudan's Upper Nile state said at least four people were killed and another injured in an attack in the disputed Kilo 10 area between Maban and Melut counties on Sunday.

Speaking to Radio Tamazuj Major General Chol Atem, the state police chief, said that the attack was allegedly carried out by a group of armed men from Maban County. 

"What we have is preliminary information, and research is underway to find out the full information of the attack," he said.

Gen. Atem said the area now remains tense since the attack citing that the attack is a violation of a local agreement barring parties from creating conflict over the Kilo 10 area.

He indicated that the state government will form a committee to investigate the incident and the motives behind the attack.

Last year, the state government called on the parties to the conflict in Maban and Melut counties to abide by the decisions of the Presidential Committee on the area.