Carjackers killed a Sudanese aid worker in the country's Darfur region, the UN said, bringing to four the number of humanitarian staff killed this year in the region's worsening unrest.
The attack happened on October 23 about 15 kilometres (nine miles) southwest of Nyala, Sudan's second largest city, the United Nations Office for the Coordination of Humanitarian Affairs (OCHA) said in its latest weekly bulletin, issued late on Thursday.
It said the head of the Sudanese Al-Sugia Charity Organisation, a non-governmental group, was killed by unidentified gunmen.
"Another staff member of Al-Sugia on board the NGO vehicle and a police officer were injured when the gunmen ambushed and hijacked the vehicle," OCHA said.
In July two local staff members of the international aid group World Vision died when Nyala became an urban battleground during fighting which officials blamed on "differences" between members of the security forces.
In June a Sudanese nurse working for an international aid agency was killed when a stray bullet went through the wall of his home in a camp for displaced people in Central Darfur.
A 10-year-old rebellion continues in Sudan's western region of Darfur but an upsurge of violence this year is mainly due to inter-ethnic militia fighting, most of it Arab against Arab.
Hundreds have been killed and hundreds of thousands displaced since January.
The cash-starved government can no longer control its former Arab tribal allies, and violent competition for resources has intensified, analysts say.