A grenade explosion wounded three children from one family at Hai Mangatain in the capital Juba on Thursday evening, several eyewitnesses said.
The children, aged between 4 and 9, were rushed by the family members to the Chinese Hospital for treatment.
The eyewitnesses told Radio Tamazuj that incident caused fear among local residents of Hai Mangatain and Hai Referendum.
The residents pointed out that unexploded bombs were not properly clearly in the two neighbourhoods.
The incident comes a few days after the United Nation warned against the danger of landmines in South Sudan.