Medicines Sans Frontiers or MSF said seven men were killed when a container full of ammunitions exploded near Thar Jath, in Leer of Unity State last Thursday.
In a statement CRN obtained on Tuesday, it said a 14-year-old boy Kume Saadi Kuony who was on a visit to relatives sustained multiple wounds.
MSF said local people set fire to the grass around the container to clear the land in preparation for farming, causing the ammunition inside to overheat and explode.
Mr Kume had no idea that the container sheltering him from the midday heat in the village of Gayiel was full of unexploded ordnance left behind following heavy fighting in the area last year.
MSF Deputy Medical Coordinator Dr Fouad Dahir reported that exploding ammunition threw up dirt, soil and grass and buried Mr Kume leaving him with multiple cuts all over his body, from shoulders down to his feet.
MSF Head of Mission in South Sudan Paul Critchley lamented that ‘once again we are confronted with the tragedy of conflict, the senseless suffering of civilians’.