Anger is high after Lou fighters massacred 71 people in the Jikany village of Torkech in May.
Clashes between rival groups in the south have taken place for generations, over resources, land or livestock.
But these well-planned attacks are no simple disputes over stolen cattle.
Women and children are now also deliberately targeted - something elders say never happened in the past.
Southern President Salva Kiir says he is "convinced beyond any doubt" that the fighting is the work of "outside forces".
Who is really responsible for the violence, and what lies ahead for Sudan, is unclear.
However, if the past is anything to go by, it will be the most vulnerable who once again suffer most.
Full story: BBC News, Wednesday, 8 July 2009
Could Sudan clashes herald return to war?
By Peter Martell, BBC News, Nasir, southern Sudan
Click on Jonglei label here below for related reports and latest updates.
