Two days of fresh fighting in Sudan's Blue Nile state have left "heavy losses" among rebel troops, the army said on Saturday, without giving casualty figures for either side.
The combat occurred west of Dindiro, some 100 kilometres (60 miles) southwest of the state capital of Ed Damazin, said Sudanese army spokesman Sawarmi Khaled Saad.
"There are heavy losses among the SPLM troops, people killed and equipment destroyed," he told AFP.
Rebels from the Sudan People's Liberation Movement-North (SPLM-N) in Blue Nile could not be immediately reached for comment.
Access to the state is restricted, making independent verification difficult.
Fighting began months ago in Blue Nile and nearby South Kordofan state between the government and ethnic minority insurgents who fought alongside the former rebels now ruling South Sudan.
The South gained independence from Khartoum last July after decades of civil war.
On Thursday the United Nations humanitarian agency (OCHA) said fighting had continued in parts of Blue Nile and South Kordofan during the first days of February.
More than 140,000 Sudanese refugees have fled to South Sudan or Ethiopia since fighting erupted last June in South Kordofan, followed by Blue Nile in September, OCHA said.
The United Nations has backed statements by the United States that there could be a famine unless urgent aid is allowed to enter the two states, where Sudan has severely restricted the work of foreign relief agencies.