The United Nations World Food Programme (WFP) said an airstrike hit two contracted trucks carrying food assistance between Dilling and Kadugli in Sudan’s South Kordofan state early on October 3. WFP said one driver was killed and that the vehicles were clearly marked as humanitarian transports.

The agency said it was still collecting details about the circumstances and the extent of damage to the food cargo, and called for a prompt, impartial investigation. WFP said the attack came a day after another truck struck an explosive device in Dilling after delivering food aid. The agency has not yet confirmed whether the October 3 attack damaged the cargo.