Fighting in a tense area of Southern Sudan last weekend killed dozens of people only weeks after some 240 people died in violence in the same area, two officials said Wednesday.
The clashes could destabilize what is soon to be the world's newest country.
Rebel leader George Athor said his forces fought with the southern military on Sunday in Southern Sudan's Jonglei state. The spokesman for the Sudan Peoples' Liberation Army, Col. Philip Aguer, confirmed that the fighting took place.
The death tolls provided by the two men varied widely. Athor said 110 people died in the fighting, mostly southern soldiers but also 12 civilians. Aguer said around 40 were killed. He didn't specify if they were soldiers or civilians, but he called Athor's toll an exaggeration.
"I don't know why he should be proud of killing. The (southern army) is trying to protect against what Gen. Athor did on the 9th and 10th of February in Fangak," he added, referring to the fighting three weeks ago.
Athor, speaking on a satellite phone from a remote hideout, said his men fought southern army troops in three locations in Fangak County on Sunday. He said his forces captured 90 weapons. The fighting has stopped, he said.
Fangak was the scene of intense fighting three weeks ago that left more than 240 people dead, mostly civilians.
After that violence, government leaders in Southern Sudan accused Athor, a former deputy chief of staff in the southern army, of committing a "massacre." Athor said the army had attacked his forces first as they were gathering in "assembly points" outlined in a Jan. 5 cease-fire agreement between his forces and the army.
The cease-fire was signed on the eve of the south's Jan. 9-15 independence referendum, which passed overwhelmingly and will see Southern Sudan become the world's newest nation in July.
The agreement was brokered with support from the United Nations peacekeeping mission in Sudan. The mission's spokesman, Hua Jiang, said Tuesday that the U.N. is "trying to assist in their negotiations."
Athor is considered the most powerful of the several southern rebels who launched rebellions against the Juba government after disputed elections last year. The south's ruling Sudan People's Liberation Movement has accused the Khartoum government of backing the rebels.
Regardless of who is backing these rebellions, they have exposed deep internal rifts within the oil-rich south which could continue to destabilize the region after it declares independence on July 9.
On Friday, Southern Sudan President Salva Kiir addressed the senior leadership of the southern army and instructed them to protect civilians at risk of attacks by Athor's forces.
Aguer said the president was right to remind the military of its role to protect civilians. He said Athor is "refusing peace, amnesty, and the cease-fire."
Since the referendum's official results were announced on Feb. 7, violence in Jonglei state and ongoing tensions in the contested north-south border zone of Abyei have cast a shadow over the euphoria of the peaceful vote.
Leaders from the north and south are meeting this week in Ethiopia to discuss economic and political relations between the two regions after the south forms its own state.