A UN report accuses the Sudanese army of carrying out rapes and looting during attacks in Darfur.
The UN says more than 200,000 have died in the conflict
It says raids by aircraft and ground forces on three towns left at least 115 people dead in February.
The large scale of destruction suggests the damage was done deliberately as part of a military strategy, it adds.
The UN says more than 200,000 people have died in Darfur since rebels took up arms in 2003. Two million have been displaced and now live in camps.
The report was issued jointly by the UN Office of the High Commissioner for Human Rights and the UN-African Union Mission in Darfur (Unamid).
It quotes witness reports of government-backed militiamen on camels and horseback setting houses on fire, shooting at residents and looting.
It also says witnesses saw members of the Sudanese armed forces joining in the attacks, raping girls and taking part in looting.
More than 30,000 people fled the attacks on the towns of Sirba, Sileia and Abu Suruj, the report says.
It describes the "major military campaign" as an attempt by the government to regain control of the northern corridor of West Darfur, and to drive out the Justice and Equality Movement rebel group.
"The scale of destruction of civilian property, including objects indispensable for the survival of the civilian population, suggests that the damage was a deliberate and integral part of a military strategy," said the report.
The UN report condemns the attacks as "violations of international humanitarian and human rights law".
It urges the Sudanese government to cease hostilities in the area, and to refrain from "launching deliberate and indiscriminate aerial attacks against civilians".
It also calls on all parties in the Darfur conflict to respect their obligations and refrain from using civilians as "human shields".