Two humanitarian workers have been killed by gunmen and three others wounded in Sudan’s South Darfur, an aid agency said.

The International Committee of the Red Cross (ICRC) said in a statement that two of its drivers were killed by gunmen on Thursday in the volatile region.

"The team was on its way back from Layba to assess the humanitarian situation of communities affected by armed violence in the region when the incident occurred," it added.

The gunmen are yet to be identified and the paramilitary Rapid Support Forces (RSF), which controls South Darfur, has yet to comment on the incident.

The ICRC called for the immediate protection of all civilians, including humanitarian workers and medical personnel.

"They must never be directly attacked," it added.

Nearly 20 aid workers have been killed in the Sudanese conflict since it erupted in April last year, according to the UN.