Sudan Sudan is to begin the disarmament of rival cattle-herding groups in Jonglei state this week, by force if necessary, the army has said.
Some 12,000 soldiers and police are deploying to collect an estimated 30,000 weapons from Jonglei civilians.
Last year, 1,100 people died in clashes between the Lou Nuer and Murle communities and tens of thousands have been displaced in fighting this year.
The two groups have a long history of stealing each other's cattle.
The violence tends to start as cattle raids and then spirals out of control, leading to revenge retaliatory attacks.
South Sudan, which gained independence from Sudan last year, is awash with small arms after decades of civil war that ended in 2005.
News of the disarmament programme came as South Sudan accused Sudan of bombing an oil installation in its territory.
The attack has not been independently verified, but the US has said it is alarmed by the reports.
"Such incidents are unacceptable and threaten to escalate tensions between the two states," US state department spokeswoman Victoria Nuland said in a statement.
Sudan has denied the claim, saying it does not attack across international borders.