Ten relief organizations working in South Sudan say the U.N. should urgently improve its peacekeeping mission in the country to protect civilians and help deliver aid to civilians affected by the country's civil war.

The groups, including Oxfam, CARE, and the International Rescue Committee, issued a joint statement in South Sudan's capital, Juba, on Friday following reports that U.N. peacekeepers failed to act when government forces targeted civilians under the U.N.'s protection, including raping dozens of Nuer women.

The U.N. peacekeeping force in South Sudan has about 12,000 armed troops who are mandated to use lethal force if necessary to protect civilians. The mission is also mandated to help the delivery of humanitarian aid.

Some 4.8 million South Sudanese, nearly half the country's population, are facing severe food shortages.