Sudan and South Sudan failed Wednesday to hammer out an agreement to resolve disputes that sparked an eruption of heavy fighting in a contested oil-rich border region last week.
South Sudan accused Khartoum's delegation of walking out of the latest round of African Union-led crisis talks, but a Sudanese minister voiced confidence that a deal will be signed when negotiations resume next week.
"They have literally walked out... We are ready to sign but Khartoum ran," South Sudan's lead negotiator Pagan Amum told AFP hours after the Sudanese delegation left Addis Ababa.
Amum said the mood between the two negotiating teams was "not good" as the talks closed.
However, Sudan's Interior Minister Ibrahim Mahmoud said they were committed to bringing a halt to the fighting.
"We are committed to a cessation of hostilities... we are both committed that we are not going to support any rebels groups," Mahmoud told AFP, speaking in English.
Senior officials from Sudan and South Sudan met Monday for the first face-to-face talks since fighting between their armies broke out last week along the border.
Mahmoud said they will resume talks next week and voiced hope that they will yield a "concrete commitment from both of us that we will stop any support for any (rebel) groups".
Chief mediator and former South African president Thabo Mbeki will visit Khartoum and Juba before talks resume, Mahmoud added.
"Mbeki will go to Khartoum and Juba to narrow the gap," he said, without giving any date for next week's talks.
The two nations have traded blame over who started the border clashes that involved air strikes and ground fighting in the oil-rich Heglig area close to the disputed border.
Tensions remain high between their armies along the border, and both sides have traded furious rhetoric.
The latest round of talks was delayed when the South accused Khartoum of "waging war" and of failing to send its defence minister who arrived in Addis only on Monday, two days after the negotiations were set to begin.
Sudan denied it was waging war and said it was committed to talks.