South Sudan's warring rivals opened the latest round of peace talks Monday to end over 14-months of conflict with negotiators warning it was the "final opportunity" to strike a deal.
Regional bloc IGAD has set a March 5 deadline for President Salva Kiir and rebel chief Riek Machar to reach a final peace agreement, but previous deadlines have been repeatedly ignored despite the threat of sanctions.
"This is the final opportunity to make progress and usher in a new era of peace in South Sudan, we must not fail," IGAD mediator Seyoum Mesfin said as talks opened in the Ethiopian capital.
Seven previous ceasefire deals have failed, and increasingly frustrated diplomats said that while they expected a deal on paper, the issue will be enforcing it on the ground.
"I'm optimistic that there will be an agreement. The patience of the regional countries is ending and the economy of South Sudan is in free fall," a Western diplomat following the talks said.
"The problem will be whether or not this agreement will be implemented."
Neither Kiir nor Machar are at talks for now, but they have agreed to set up a transitional unity government to take power by July 9.
Fighting broke out in South Sudan, the world's youngest nation, in December 2013 when Kiir accused his sacked deputy Machar of attempting a coup.
Over two dozen armed forces -- including government soldiers and allied militia backed by Ugandan soldiers on one side, and a range of rebel factions on the other -- have been battling it out for the last 14 months.
"Now is the time to compromise," said British special envoy Matt Cannell. Britain, along with the United States and Norway, form the "Troika" nations who are backing the peace process.
Fighting has raged this month in the northern Upper Nile state, with the government warning that rebel forces were splintering, making any negotiations increasingly complicated.
The UN estimates that 2.5 million people are in a state of emergency or crisis, meaning they are just steps short of famine.
No overall death toll for the war has been kept by the government, rebels or the UN, but the International Crisis Group estimates that at least 50,000 people have been killed.