The residents of al-Jeer Sureaf are among about 1.5 million Africans who live in squalid tent cities across Darfur after being driven from their farms by the fighting, which broke out in February 2003 when African tribes rebelled against the Arab-led government.
In retaliation, the United Nations says, the government has bombed villages and armed the Janjaweed militias. Tens of thousands of people have died from hunger, disease and violence; the Bush administration has described the crisis as genocide.
Worries over security have increased significantly since last month, when two aid workers from Save the Children were killed by a land mine. U.N. officials have blamed one of several African rebel groups for the attack. Tensions also increased when African Union monitors reported that 18 Sudanese of Arab origin were taken hostage while traveling on a bus last week.
Rebel groups deny setting the mines; they have also accused the Janjaweed of forcing 30 ethnic Africans from a bus on Sunday and shooting them. The African Union said it was investigating.
Pronk, of the United Nations, blamed rebels for stepping up attacks, harassing aid workers and stealing food from convoys. Some refugees said they believed the government assault here might be retaliation for stepped-up rebel actions.
"The incident of the mine is a very big concern. People who lay mines are cowards," Pronk said. "This kind of behavior has to stop because insecurity and violence [are] escalating. We are in a dilemma of increasing difficulties on the ground, increasing fighting, increasing number of people fleeing. But it's more difficult to help them because of the violence."
As camp residents here tended to their wounds and salvaged their belongings from smoldering huts, they described the ordeal that began at 3 a.m. when the troops entered their sleeping settlement. A midwife at the clinic said she had tied the beds of the maternity ward together and armed herself with knife.
Lying on a metal cot with several broken ribs, Taja Ibrahim, 28, writhed in pain and took gulps of air, her whole body heaving as she struggled to breathe. She said that the government troops had beaten her with sticks and guns but that she was too afraid of the Janjaweed to return home.
Nearby, Halima Hassan Adam, 21, cradled her newborn baby in her arms as she sat disconsolately outside their former home, now just a pile of singed straw. Her 3-year-old son's eyes still stung from the tear gas. The young mother bent down and searched the ground, hoping to save a few beans that had been crushed in the attack.
"I delivered my baby here 22 days ago," she said. "This was the only home we had. Now since yesterday, we have had no food or water. I am so scared. I am just holding my children tight and praying."
In the scorched camp, lizards scurried over charred blankets and donkeys nosed through the remains of shelters. But by dusk, women were starting to rebuild their homes, knotting vines of grass to long tree branches to make circular shelters. Meanwhile, aid workers filtered back into the community, surveying the ruins with horror.
"It makes you so angry you want to cry," said one worker, who spoke on condition of anonymity. "It's like the government wants to get rid of people in the town and send them to the desert where they are closer to death."
Staff writer Colum Lynch at the United Nations contributed to this report.