Sudan and rebels traded accusations on Monday but vowed to press ahead under African Union mediation with their first peace talks in nearly a year.
The United Nations has urged Khartoum and rebels from the Sudan People's Liberation Movement-North (SPLM-N), who began talks in the Ethiopian capital on Thursday, to declare an immediate ceasefire so aid can reach more than one million civilians.
"The talks are at a deadlock. They are at a deadlock and we couldn't move anywhere because of the intransigence of the Khartoum government," head of the rebel delegation, Yassir Arman, told AFP.
He said Khartoum wants "to freeze this war without giving any solutions to the humanitarian situation and the political situation".
The government denied talks have stalled and accused SPLM-N of raising issues unrelated to the two warzones of South Kordofan and Blue Nile, where the ethnic rebels have been fighting for almost three years.
Khartoum is "ready to continue the dialogue to reach a comprehensive solution for the two areas," Sudan's delegation said in a statement.
Ibrahim Ghandour, who leads the Sudanese negotiators, said at the start of talks that they should focus on security, political and humanitarian aspects "concurrently and as one package" for South Kordofan and Blue Nile.
The rebels have said humanitarian issues should be addressed first. They want the wars in "marginalized areas" including Kordofan and Blue Nile to stop ahead of a national constitutional conference to address the root causes of conflict.
Arman said on Monday that while there is concern the dialogue could collapse, "we are ready to do whatever that will let the talks continue".