Jar el-Neby Abdel Karim, commander of a breakaway arm of the Sudan Liberation Movement – not a signatory to a 2006 peace accord - said a government plane dropped around 15 bombs near a water station in Malam al-Hoj, about 150 km south of el-Fasher.
"They fired on civilians. One citizen was killed and four were wounded," he said.
Abdel Karim said Janjaweed fighters riding horses and camels, and government troops in 12 vehicles, had also attacked a village in West Darfur earlier in the day, killing four people in Abu Surouj, south of Jebel Moon.
The Sudanese army spokesman dismissed reports of an attack near Jebel Moon: "The Sudanese military conducted ordinary patrols, but there were no clashes."
He said the incident could have been a tribal clash, and that the rebel fighters had wrongly blamed the government. He also denied that a government plane had shelled the Malam area.
Thousands displaced
The UN has said up to 200,000 people have been killed and more than 2 million displaced in ethnic and political conflict in Darfur that flared in 2003 when rebels took up arms against the government. An African Union peacekeeping force of 7,000 has so far failed to quell the violence.
Rights groups accuse Khartoum of arming Arab Janjaweed militias, blamed for a host of atrocities in the region, to suppress anti-government fighting. Khartoum denies that it has supported the Janjaweed, instead, calling them criminals.
Sudan's government has agreed to a UN "heavy support package" for Darfur of about 3,500 military personnel.
Khartoum, however, has not approved the hybrid UN-AU force of more than 20,000 troops, nor has it approved UN police assistance as necessary to stem violence in Darfur.