Sudanese officials were not immediately available to comment. U.N. officials have said killing in the area had decreased since January.
"Sudanese forces came in trucks and attacked two places south of al-Fasher ... They killed a number of civilians and injured others ...," said Bosh Shag Umar, a local commander with the Sudan Liberation Movement (SLM).
U.S. Secretary of State Condoleezza Rice was in Sudan last week and told Sudanese officials she wanted to see "actions not words" to quell violence in Darfur.
The government and the two main rebel groups in Darfur signed a declaration of principles in the Nigerian capital Abuja earlier in this month.
The agreement deals with broad-based principles for talks, but leaves the main issues to be discussed in more detail on August 24 when African Union-sponsored negotiations resume.
Umar said the first attack was in the Abu Hamra area on Sunday morning and the second in the Sheng al-Tobei area later the same day. Both areas are south of al-Fasher, capital of Northern Darfur State, he said.
Around 40 trucks full of troops and around three helicopters razed three villages to the ground in the Abu Hamra area, around 120 km (75 miles) south of el-Fasher.
Between 40 and 42 trucks, without helicopters, attacked Sheng al-Tobei village and 20 tents belonging to families forced out of their homes by earlier fighting, he added.
Umar said the government troops used rocket-propelled grenades in the attack, around 90 km (55 miles) south of el-Fasher.
He could not say how many people died in either attack.
Both towns are on the main road between el-Fasher, capital of Northern Darfur State and Nyala, capital of Southern Darfur State, he added.
Tens of thousands have been killed and around 2 million driven from their homes since rebels launched a rebellion in early 2003, accusing the government of neglect and arming militias to burn and loot villages.
The government denies the claim.
- Reuters - Thomson Reuters Foundation
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