South Sudan's government confirmed the deal was signed after face-to-face talks between President Salva Kiir and opposition leader Riek Machar in Sudan. The discussions followed their meeting last week in Ethiopia that was their first in nearly two years, AP reported.
The new agreement also calls for the opening of corridors for humanitarian aid, the release of prisoners and the withdrawal of forces. The African Union and East African regional bloc are asked to provide forces to oversee the cease-fire. South Sudan in the three years ahead also will prepare for elections.
Tens of thousands have been killed in South Sudan's five-year civil war, which has created Africa's largest refugee crisis since the 1994 Rwandan genocide and left millions near famine. Multiple attempts at peace deals have failed in the past, and the United States, the country's top humanitarian donor, has grown increasingly frustrated.
The two sides expressed mixed emotions shortly after the agreement.
"This is the president signing, so everyone in the government will have to implement it," said government spokesman Ateny Wek Ateny. "We're very happy with this deal."
Expect a power-sharing agreement in the next couple of weeks, Ateny said.
Meanwhile, opposition spokesman Mabior Garang said there was no guarantee the cease-fire will work. "However, the involvement of the region is more serious now. We are cautiously optimistic."
The latest cease-fire in December was violated within hours.