Conflict and drought have ravaged four countries across North Africa and the Middle East, leaving more than 20 million people in desperate need of food.
The U.N. says nearly 5 million people do not have enough food, and it issued a formal famine declaration for Unity State in the north-central part of the country.
The U.S.-backed resolution fell two votes short of adoption Friday. It would have been the Security Council's most recent attempt to stabilize the restive country.
At a time when South Sudanese need aid more than ever, staffers from one of the biggest humanitarian groups in the country were expelled — with no explanation.
In a meeting of the U.N. Human Rights Council, commission chief Yasmin Sooka reported murder and rape on an "epic" scale. "We are running out of adjectives to describe the horror," she said.
More than 100 Japanese peacekeepers have landed in the capital of South Sudan. Their mandate includes using force, if necessary, to protect aid workers and others.
An independent review found "conflicting orders" within the United Nations mission in Juba resulted in failure to respond to an attack during which South Sudanese soldiers raped Western aid workers.