NAIROBI, Kenya -- South Sudan's top U.N. aid official on Saturday hailed a new peace deal and called for food aid to flow to counter the risk of mass hunger.
A military spokesman said a cease-fire would take hold, but wary skepticism remained: This is the conflict's second peace deal.
The truce signed by President Salva Kiir and former Vice President Riek Machar late Friday in neighboring Ethiopia calls for a cessation of hostilities within 24 hours and unhindered humanitarian access.
Though it is the second peace deal of the nearly five-month conflict, the two leaders did not attend talks that forged the first cease-fire in January. This time they stood face to face, a hopeful sign one week after U.S. Secretary of State John Kerry met with Kiir in South Sudan's capital and spoke to Machar by phone. Days later U.N. Secretary-General Ban Ki-moon flew in, adding to the pressure.
The warfare has thrown an extremely poor country up against the edges of severe hunger. A new analysis released Saturday by the World Food Program, Save the Children and South Sudan government found food needs deepening to "alarming" levels in areas isolated by conflict, particularly several counties in Unity state, where up to 75 percent of people face severe hunger.
The fighting, which has often pitted Kiir's ethnic Dinka against Machar's ethnic Nuer, has killed thousands of people, often in what a new U.N. report this week said were gross violations of human rights "on a massive scale." More than 1.3 million people have fled their homes, and aid officials fear that mass hunger will set in later this year.
"Big news from Addis," Toby Lanzer, the top U.N. aid official in South Sudan said on Twitter on Saturday. "Calling on both parties to facilitate deliveries of emergency relief to people in need now: open roads for truck convoys & rivers for barges."
Asked by The Associated Press if there is any evidence that the parties will open up aid access, Lanzer replied: "It's a better result than many would have expected."
Among others voicing caution was John Prendergast, the co-founder of the Washington-based Enough Project, which does advocacy work in eastern and central Africa.
"We will know very quickly whether the parties are serious, as they are right now poised to attack each other in a number of volatile locations on the front lines of the war. It is crucial to deploy the regional civilian protection force and cease-fire monitors to ensure some measure of compliance. If this falls apart, the fighting will enter an even bloodier phase as the stakes continue to increase," Prendergast said.
Cecilia Millan of Oxfam said it remains to be seen whether civilians will have enough faith in the deal to to return home and plant crops.
Asked if Kiir's military would hold up its side of the cease-fire deal, the South Sudan military spokesman, Col. Philip Aguer, responded "definitely." He said the new deal has a better chance of holding since Machar signed it himself. But he acknowledged violence could return if rebels, perhaps if there are some Machar can't control, continue attacks.
"There can still be a problem if they don't listen and don't stop attacking, then definitely the government forces will have to defend themselves," Aguer said.
International pressure had been growing for at least a brief cease-fire to alleviate hunger fears. Lanzer included in his tweet the phrase "May Month of Tranquility" as a Twitter hashtag. Aid officials say if residents don't immediately return home and plant crops before seasonal rains arrive in force in June, then the country risks mass hunger and perhaps famine.
The World Food Program says 3.2 million people need food assistance. WFP says it has a funding shortfall of $261 million.
"A hunger catastrophe can still be avoided, but humanitarian agencies must be allowed to reach tens of thousands of people in need before it's too late," said Mike Sackett of the WFP in South Sudan. "It is absolutely critical to stop fighting and other obstacles that prevent life-saving aid deliveries."
Kiir and Machar agreed to establish a "transitional government of national unity" that will lead to new elections, said a statement by the regional bloc IGAD, which brokered the talks. The two also agreed to meet again in a month, while IGAD leads talks on the terms of the transition.
South Sudan is a largely Christian and animist nation that broke off from the Muslim-dominated Sudan after a 2011 referendum.