Clashes erupted between Sudan's army and rebels in the western Darfur region and in a southern state, killing dozens of people including civilians, the sides said on Friday, the latest violence in the country's borderlands.
Sudanese President Omar Hassan al-Bashir is battling an alliance of rebel groups operating in Darfur and two states bordering its neighbour South Sudan.
Sudan accuses South Sudan of supporting the rebels, while Juba says Khartoum funds militias in South Sudan. Diplomats say that both allegations are credible.
South Sudan split from Sudan last year under a 2005 peace deal that ended decades of civil war, but the two have remained at odds over a range of issues and conflict has continued to plague their borderlands. The nations came close to war in April.
Sudan's military spokesman al-Sawarmi Khalid said the army killed 77 rebels in two separate clashes on Thursday in South Kordofan, a state bordering South Sudan, and in North Darfur state.
The army is fighting rebels of the Sudan People's Liberation Movement-North (SPLM-North) in South Kordofan and Blue Nile, another state bordering South Sudan.
Khalid said SPLM-North rebels attacked the village of Hajr al-Dum in South Kordofan. He said 45 rebels and 21 civilians were killed in the violence, among them women and children.
"The armed forces are continuing to expel the rebels from the area," he said.
The SPLM-North gave a different account, however. It said its forces had attacked an army position in the area of Hajr al-Dum and had driven out all troops from the area. One soldier was killed and five wounded, spokesman Arnu Lodi said in a statement.
Military spokesman Khalid said the army repulsed a rebel attack on the village of al-Adradib in North Darfur, killing 32 insurgents. Several soldiers were killed or wounded, he told Sudanese state television, without giving any figures.
However, the Justice and Equality Movement (JEM), one of the biggest Darfur rebels groups, said dozens of soldiers were killed when JEM repulsed an army attack on the village.
"The air forces bombed the area and killed tens of civilians," JEM spokesman Jibril Adam said.
He also said the army attacked the area of Tanga in South Darfur. "Our forces dealt a major blow to the Sudanese Armed Forces and their militias in Tanga," Adam said.
Events in Darfur and South Kordofan are hard to verify due to a lack of access for journalists to the remote areas.
The SPLM-North, JEM and two other Darfur rebels groups formed an alliance last year with the aim of toppling Bashir.
Sudan and South Sudan are currently holding talks in Ethiopia to discuss a border security agreement.
They have already signed an interim deal to restart oil exports, the lifeline for both nations. But Sudan wants a border deal before it will allow its landlocked neighbour to export its oil through northern pipelines.