South Sudan says it is sending its army to the disputed oil-rich Abyei region, along the border with Sudan, following ethnic clashes that have killed more than 40 people.
The government has accused UN peacekeepers in the region of failing to protect civilians displaced during the latest spate of violence.
The deployment could reignite tensions with Sudan over the contested territory.
The ethnic clashes are between the Ngok Dinka community and the Misseriya Arab community who cross from Sudan looking for pasture.
The two groups have long-running disputes that have displaced thousands of people there over the years.
A referendum to resolve the status of Abyei was supposed to be held following a peace deal in 2005, but the vote has never materialised.
The latest violence comes as South Sudan grapples with rising inter-communal fighting in various parts of the country.
Violence has also been reported in the northern Unity State which borders Abyei, where armed groups have clashed over cattle.
On Monday, nearly 30 people were killed in Leer county in the latest bout of fighting that began in late February.
Analysts warn that the fighting threatens the fragile peace deal in the world’s youngest nation.