Insurgents in Sudan's South Kordofan state said on Sunday they have repulsed government soldiers who tried to seize two rebel-held villages near the state capital of Kadugli.
The fighting is the latest since Sudan and South Sudan -- which Khartoum accuses of backing the rebels -- resumed African Union-led talks on Tuesday in Ethiopia to resolve security and other crucial issues.
Government forces tried on Friday to take Dloka village, 13 kilometres (eight miles) south of Kadugli, as well as a second community northeast of the government-controlled capital, said Arnu Ngutulu Lodi, spokesman for the Sudan People's Liberation Movement-North (SPLM-N).
"They have tried many times to control these areas," which, he told AFP, have been in SPLM-N hands since fighting began in June last year.
Lodi said battles for the two villages left nine government troops and one rebel dead. Casualty claims are difficult to verify with access to South Kordofan restricted.
Asked for comment, the army said it would issue a statement later.
Both sides earlier agreed there had been fighting on Thursday at another location, Hajar Al-Dom village northeast of Kologi town, but disputed what had happened.
Ethnic minority insurgents from the SPLM-N previously fought alongside the rebels from southern Sudan who waged a 22-year civil war which ended in a 2005 peace deal that led to South Sudan's independence last year.
Khartoum accuses the government in Juba of backing rebels in the north, a charge which analysts believe despite denials by South Sudan's government, which in turn has accused the north of backing rebels in the South.
Sudan and South Sudan fought along their undemarcated frontier in March and April, sparking fears of wider war and leading to a UN Security Council resolution which ordered a ceasefire and the AU talks which resumed last week.
In early August those negotiations led to a breakthrough deal on fees due by Juba for shipping its oil through the north's pipeline for export. But Sudan says the oil deal will not be implemented unless security issues are settled first.
The US ambassador to the United Nations, Susan Rice, on Thursday said Sudan's refusal to accept a demilitarised zone with South Sudan risks sparking "outright conflict."
Rice said it was "equally disappointing" that Khartoum refused to implement the oil accord until all differences between the two have been settled.
South Sudan has agreed to an AU map of the demilitarised zone, but Khartoum has not. Its opposition has focused on the inclusion of a disputed area south of the Bahr el-Arab/Kiir River.
Britain has backed AU and UN calls for Khartoum to accept the map, saying it has no bearing on the line of a permanent border.© ANP/AFP