Rebels in Sudan's Darfur on Monday denied killing 13 civilians, calling government claims of their involvement a fabrication.
The official news agency SUNA said the "innocent citizens" died on Saturday in an ambush on a commercial convoy about 30 kilometres (19 miles) west of El Fasher, the North Darfur capital.
State governor Osman Kbir blamed "armed movements", a term officials use to refer to rebels, calling the attack "heinous aggression".
But Hussein Minnawi, a member of the political bureau of the Sudan Liberation Army faction headed by Minni Minnawi, said the claim was "clearly something fabricated."
"Our forces were not there and it is not usual that our forces can do anything like that," he said.
The faction has operated in North Darfur but Hussein Minnawi told AFP the area where the civilians died "is occupied by Janjaweed and the militia of Kbir."
A Western diplomat has told AFP that Darfur's rebel groups prefer to target government installations, not civilians.
Minni Minnawi and other insurgents from Darfur's black tribes rose up 11 years ago against what they said was the domination of Sudan's power and wealth by Arab elites.
In response the government turned to "Janjaweed" militia recruited from Arab tribes. They were accused of committing atrocities against civilians, and have since been incorporated into official paramilitary units.
Authorities acknowledge "they are increasingly losing control over paramilitaries, who have been the main source of insecurity in Darfur for two years", the International Crisis Group think-tank said in a January report.
Militias in search of resources have turned on each other, and sometimes against the government, while violent crime has increased.