The United Nations refugee agency has expressed alarm at the apparent renewal of a "scorched earth" policy in Darfur.
Many villages were burned in 2004
"The burning of villages seems to have resumed," Jennifer Pagonis, spokeswoman for the office of the UN High Commissioner for Refugees (UNHCR) said.
"This gratuitous act is clearly a message to the former residents not to return home."
The UN says the conflict has already claimed 180,000 lives and driven about two million people from their homes.
UN staff visiting a village in western Darfur heard that 200 families had been forced to flee by the government-backed Janjaweed militia a year ago.
Last week, local people said, the militia returned and set fire to the village. It had been reduced to ashes, the UN staff said.
The refugee agency says that in October and November of last year about 55 abandoned villages near the town of Masteri were burned to the ground.
If the practice has resumed and continues, aid workers fear, Darfur's social and demographic structure will be changed for ever.