The World Food Program said in a statement released Sunday that driver Jamal Al Fadil Farag Allah, a Sudanese national, was killed in an attack by two assailants on Saturday. It said he was driving a fellow staff member who survived the attack near Hilat Yatu, about 80 kilometers (49.71 miles) north of Kadugli, the capital of South Kordofan.

WFP Executive Director Ertharin Cousin condemned the attack saying it is unacceptable for humanitarian workers to face attacks while they are working on the front lines of hunger.

Sudanese troops are fighting rebels, who were once aligned with what is now South Sudan, in Kordofan near the countries' shared border. The U.N. refugee agency says hundreds of thousands of people have fled the conflict