The Sudanese government and rebels said they failed to agree on a ceasefire as three weeks of negotiations to end a three-year-long conflict concluded on Tuesday amid an uptick in violence.
Khartoum has been fighting an insurgency in the southern provinces of Blue Nile and South Kordofan since 2011, mounted mostly by former civil war fighters who were left in Sudan after South Sudan seceded that year.
Talks collapsed largely because the rebels insisted that a ceasefire in the two regions be negotiated in conjunction with one in neighbouring Darfur, where a conflict that saw the government accused of genocide a decade ago has rumbled on.
"We see these as separate issues from each other, and each region has its specific needs," said Hussein Karshoum, a member of the government delegation.
He said the talks, which took place in the Ethiopian capital under the auspices of an African Union panel headed by former South African President Thabo Mbeki, were expected to resume in January.
On Monday, both sides reported clashes in South Kordofan.
The rebel Sudan People's Liberation Movement-North Sector (SPLM-N) also wanted to link the talks with political developments in Khartoum.
President Omar al-Bashir, who has ruled the country for 25 years and is a candidate in April elections, announced a "national dialogue" in January, but little progress has been made.
The political deadlock has prompted opposition politicians to symbolically join forces with the armed groups. A broad array of groups signed a unity agreement last week that they hoped would strengthen the negotiating position of the SPLM-N.
But the government warned political leaders would pay a price for tying their fate to the rebels, and arrested two of them days after the deal.
"The government is not serious about the national dialogue and is just buying time for the re-election of a president who is wanted by the International Criminal Court," said Yasir Arman, secretary-general of the SPLM-N, in a reference to the ICC's indictment against Bashir for war crimes, genocide and crimes against humanity.
"The regime has no solutions for the two areas except war and starvation," Arman said.
