Rebels from Sudan's Darfur region said on Wednesday they killed 11 government troops in an ambush in South Kordofan state during the Muslim holidays of Eid al-Fitr, but the army denied any such incident.
The incident took place on Monday between El Muglad and the railway town of Babanusa, about 50 kilometres (30 miles) east of East Darfur state, according to Abdullah Moursal, spokesman for the Sudan Liberation Army's (SLA's) Minni Minnawi faction.
In addition to those killed, "we took some of them as prisoners," he said, adding there were no rebel fatalities.
Sudanese army spokesman Sawarmi Khaled Saad denied the whole report. "There were no security disturbances during Ramadan or Eid," the holiday marking the end of the Muslim holy month, he told AFP.
The SLA began their rebellion in Sudan's far-western Darfur region in 2003 when black African tribes rose against the Arab-dominated Khartoum government.
Last year, SLA factions and Darfur's Justice and Equality Movement joined in a Revolutionary Front with insurgents from the Sudan People's Liberation Movement-North (SPLM-N) who are fighting in the South Kordofan and Blue Nile states.
The front seeks the overthrow of the Khartoum regime which it sees as unrepresentative of the country's political, ethnic and religious diversity.
Khartoum accuses South Sudan of backing the rebels, and says security issues must be settled before an August 4 agreement on oil fees can be implemented.
The deal, worth billions of dollars to Khartoum, covers fees due by Juba for shipping its oil through the north's pipeline for export. In January, the South shut its oil production after accusing the north of theft.
The South Sudanese government in Juba denies backing insurgents north of the border and accuses the north of backing rebels in southern territory.
Conflict in Darfur peaked years ago and has killed at least 300,000 people, according to UN estimates. The government says 10,000 have died.
Clashes between rebels and government troops, kidnappings, banditry and inter-ethnic fighting continue in the Darfur region, although Khartoum last year signed a peace deal with rebel splinter factions.
In South Kordofan and Blue Nile, the United Nations says more than 650,000 people have been displaced or severely affected by fighting