Six people including a senior local administrator were killed in an ambush by armed men in the Abyei region claimed by both Sudan and South Sudan, local officials said.
The oil-rich region experiences frequent bouts of violence, where rival factions of the Dinka ethnic group — Twic Dinka from South Sudan's neighboring Warrap State, and Ngok Dinka from Abyei — are locked in a dispute over the location of an administrative boundary.
Abyei Deputy Chief Administrator Noon Deng and his team came under attack along the road from Abyei to Aneet town when they were returning from an official visit to Rummamer county, where they were celebrating the New Year, government officials said.
"His driver and two bodyguards plus two people of national security were all killed," Tereza Chol, a South Sudanese lawmaker, told Reuters.
Bulis Koch, the information minister for Abyei Administrative Area, blamed the Sunday evening attack on armed youth from Twic County of Warrap State, and said the bodies had not been retrieved as of Monday morning.
His counterpart in the Warrap State William Wol said it was still early "to point fingers."
The incident is the latest in a region where dozens were killed in ethnic clashes in November.
Straddling an ill-defined border between Sudan and South Sudan, Abyei has been claimed by both countries since Juba declared independence from Khartoum in 2011.
It has a special administrative status, governed by an administration comprising officials appointed by both countries.
South Sudan erupted into civil war shortly after independence, which pitted President Salva Kiir and his allies against his Vice President Riek Machar.
A peace agreement signed in 2018 is largely holding, but the transitional government has been slow to unify the various factions of the military.