Warring rivals in South Sudan missed a 60-day deadline Sunday to forge a unity government, despite warnings of famine and the threat of sanctions if fighting continues.
Pressured by growing international condemnation of the war, the two sides had agreed on May 9 to forge a power-sharing government by Sunday.
Stop-start peace talks which began in January officially resumed on Monday in the Ethiopian capital, but the two sides failed to meet for the rest of the week.
On Saturday, Ethiopia's foreign ministry, which is hosting and helping to mediate the talks, announced the launch of talks once again.
Talks will focus on signing a cessation of hostilities agreement -- after three previous deals have collapsed -- as well as on discussing a "transitional government of national unity," the ministry said in a statement.
Aid agencies condemned the inaction of leaders to stem the fighting.
"Today, the people of South Sudan expected a political agreement that would deliver a transitional government to steer them out of conflict," Oxfam's South Sudan director Tariq Riebl said in a statement Sunday.
"Instead, the leaders of South Sudan have failed to set aside their differences, and fighting continues to ravage the country as a famine looms."
The UN Security Council threatened on Friday to slap sanctions on leaders, ahead of a South Sudan visit by its ambassadors next week.
"The actions of President Salva Kiir and former vice president Riek Machar in continuing to pursue a military solution to this conflict are unacceptable," said the 15-member council.
Thousands of people have been killed and over 1.5 million have fled almost eight months of fighting between government troops, mutinous soldiers and ragtag militia forces divided by tribe.
The UN has said the food crisis is the "worst in the world."
Six aid workers were killed this week in the northern Maban region in battles between rampaging militia fighters, forcing the UN to pull out more than 200 workers supporting over 127,000 Sudanese refugees.
UN aid chief in South Sudan Toby Lanzer reported things were calm in the Maban area Sunday, but the area remains volatile.
"This humanitarian crisis is nothing short of a man-made disaster," Riebl added.
"The impact of this conflict -- and the complete inability of both parties to bring it to an end -- has been catastrophic."
South Sudan warring rivals miss deadline for unity government