(CNN) -- A heavily armed militia attacked tribesmen during a weekend cattle drive in strife-wracked South Sudan, a government official reported Sunday, leaving behind dozens of dead and possibly kidnapping hundreds of others.
Unarmed civilians "were murdered in cold blood" while herding their livestock to camps along the Sobat River, near the Ethiopian border, Akobo County Commissioner Goi Jooyul said in a statement on the attack. He identified the assailants as members of the Murle ethnic group and the victims as the Lou Nuer, two factions that have been battling over grazing lands and water rights in the world's newest nation.
The attackers overwhelmed government troops who were guarding the herders, killing 14 of them, Jooyul said. In all, 103 bodies had been found and hundreds of families were missing, he said.
"The survivors have narrated use of heavy weaponry including RPGs by the assailants and use of spears and machetes by some," he said. Meanwhile, he said poor roads were hampering the search for those still missing, including an undetermined number of children, as well as thousands of head of cattle.
The Murle-Lou Nuer conflict is centered in Jonglei state, which borders Ethiopia. Sporadic attacks have persisted despite a peace accord signed in May, Jooyul said.
South Sudan became independent in July 2011. In January 2012, the central government declared Jonglei a humanitarian disaster area and called for international assistance in restoring security.
Journalist Isma'il Kushkush contributed to this report for CNN.