Peace talks between the two warring parties in South Sudan have been suspended indefinitely.
President Salva Kiir and his rival, rebel leader and former vice president, Riek Machar, had been meeting in Ethiopia since Tuesday, but the talks were adjourned on Friday with no peace agreement in place.
No further meetings have been scheduled.
Ethiopian Prime Minister Hailemariam Desalegn said in a statement on Friday that he regretted "the talks did not produce the necessary breakthrough", adding that the failure was disappointing for mediators and observers who had tried their best to urge the warring factions to make concessions for peace.
"The consequences of inaction are the continued suffering of you, the people of South Sudan, and the prolonging of a senseless war in your country," the statement said. "This is unacceptable, both morally and politically."
Meanwhile, UN Secretary General Ban Ki-moon said Friday he was profoundly disappointed with the failure of both sides to reach a peace deal to end the 14-month conflict, but said talks should continue.
Ban said the leaders failed "to display statesmanship" but he nevertheless called "for the continuation of the negotiations."
Fighting erupted in December 2013 after a political dispute in which Kiir sacked Machar.
The fighting has killed more than 10,000 people and driven more than 1.5 million from their homes. The conflict runs along ethnic rifts that pre-date independence.
At least 113,000 civilians have fled to UN bases for protection as government troops and fighters are accused of waging terror campaigns of rape and killing.
On Thursday, the mediator said the talks had extended to Friday to allow the two sides to finalise details of power sharing.
An African Union report, yet to be officially released, calls for Kiir and Machar to be barred from a transitional government and for the oil-producing country to effectively be placed under AU control, sources and a draft of the report said.
Source: Al Jazeera and agencies