A convoy attacked by rebels who killed nine soldiers in Sudan's Kordofan region was carrying fuel for an international peacekeeping mission, Sudan's foreign ministry has said.

The convoy was transporting fuel for the United Nations Interim Security Force for Abyei (UNISFA), the ministry said in a statement released late Wednesday.

It was the first official comment on the incident that occurred Saturday near Dilling, between the South Kordofan state capital Kadugli and El-Obeid, North Kordofan's capital, which is home to an air force base and an oil refinery.

The foreign ministry blamed the Justice and Equality Movement (JEM), a Darfur-based group, for the attack.

Both the JEM and the Sudan People's Liberation Army-North, whose rebellion is concentrated in South Kordofan, separately claimed an attack against a government military convoy in the area.

UNISFA could not be reached for comment.

A resident of the South Kordofan state capital, who is familiar with the incident, told AFP Thursday that witnesses reported that the military launched a helicopter strike against the fuel tankers in an effort to stop them falling into rebel hands.

"Some people are saying the SAF (Sudan Armed Forces) managed to bomb one or two" of the fuel trucks, which were seen burning, said the resident, who asked for anonymity.

Sudan's army spokesman, Sawarmi Khaled Saad, told AFP it was the rebels that destroyed the trucks after looting the fuel.