A United Nations official has accused Sudanese government troops of deliberately attacking civilians in the western Darfur region, killing 11 people.

The spokeswoman for the U.N. human rights agency, Praveen Randhawa, Friday said Sudanese armed forces appear to have "launched a deliberate and unprovoked attack" in the town of Sirba two weeks ago.

Randhawa said witnesses describe attackers shooting civilians, looting property and torching homes during the Nov. 11 violence. She said one woman burned to death in her home.

Randhawa said Sudanese government officials confirmed the use of force in the incident, but said it was in response to a rebel ambush.

The U.N. official said there is no evidence to support the government's version of events.

Earlier this week, the top U.N. humanitarian official, Jan Egeland, said Sudanese government forces, militias, rebels and Chadian armed opposition groups are roaming freely in refugee camps across Darfur.

Egeland also accused Sudan's government of arming new militias to combat rebels in Darfur.

An African Union force has not been able to stem the violence in the region.

Egeland said four million people in Darfur are in need of emergency aid.

Some information for this report was provided by AFP and AP.