South Sudan's warring factions have signed a new agreement to cease hostilities and protect civilians in the latest effort to calm a devastating civil war.

The two sides also signed an agreement to grant humanitarian access to conflict-affected areas after days of talks in neighboring Ethiopia brokered by the Intergovernmental Authority on Development regional bloc.

The cease-fire is set to begin first thing Sunday morning.

South Sudan is entering its fifth year of civil war, and no one knows how many tens of thousands of people have been killed in the world's youngest nation. Parts of the East African country are on the brink of famine, and well over a million people have fled abroad.

The U.S. calls the deal "the last chance for the implementation of the peace process."