Death in Darfur: a bloody conflict in western Sudan has taken the lives of thousands and threatens a million more.

Under the wide arms of an acacia tree, Khadija Adam Ahmed, 47, told how Sudanese soldiers stole her 75 cows during an attack on her village, shot at her feet to keep her from running, and then blocked the road to the refugee camps across the border in Chad.

During the night, Ahmed and 30 families fled their village in Darfur--a vast, arid region of western Sudan. They evaded soldiers and marched through mud until they were finally able to lie down under desert shrubs near the Chadian border.

Last month, in the sprawling Oure Cassoni refugee camp in Chad, Ahmed stood with dozens of others, mostly women and children, all waiting for a tent and a bag of ground corn.

Ahmed--along with a million other Darfurians--has been displaced by a war in western Sudan that pits African Arabs against black Africans, Muslims against Muslims. It was sparked in February 2003 by a rebel movement demanding greater political and economic rights for black Darfurians. The Arab-led Sudanese government responded with helicopter gunships and planes loaded with bombs.

But the most ruthless weapon has been the Janjaweed--Arab militias on horses and camels. They are accused of looting and torching villages, and driving black-African villagers off their land, raping and killing thousands of them in the process. The Sudanese government denies any relationship to the Janjaweed, but refugees, aid workers, and human-rights groups say the links are strong.

A HUMANITARIAN CRISIS 

Darfur now faces what has quickly become one of the world's worst humanitarian crises. The United Nations estimates that the conflict has killed 50,000 civilians and displaced more than a million. Around 180,000 refugees, most of them black Darfurians, have fled into Chad.

Sudan is under mounting international pressure to rein in the militias and restore security to Darfur. The Bush administration has pushed the UN Security Council to proceed with sanctions against Sudan. Also, peace talks began last month in Nigeria between Sudanese government officials and two black-African rebel groups: the Sudan Liberation Army and the Justice and Equality Movement.

UN officials, however, continued to document attacks in Darfur in August.

"There is no improvement in terms of safety, there is more fighting," said Jan Pronk, the UN Secretary General's special representative for Darfur. "The humanitarian situation is as bad as it was."

Meanwhile, the flow of refugees continues. Hawa Hassan Ahmed, 29, came to the Oure Cassoni camp following an attack by the Janjaweed. Her 6-year-old son was shot and killed before her eyes. Her 4-year-old son had his throat slit. She escaped alone on a donkey. The Janjaweed, she said, echoing the reports of other refugees, seemed to be accompanied by Sudanese military planes overhead.

UN agencies have called for more than $236 million in aid. But for many refugees, camps have provided little relief. The Centers for Disease Control in Atlanta found a 38 percent malnutrition rate among children under 5 in Chad's camps.

MOUNTING CASUALTIES

The Agency for International Development estimates 300,000 deaths by year's end, even if aid arrives quickly, and up to a million if it does not.

UN officials say their efforts to deliver water and relief supplies have been foiled by bad weather and difficult terrain. The Sudanese government has prevented aid workers from entering some areas, citing security concerns.

At Oure Cassoni, the camp's most fragile, malnourished children waited for cups of fortified milk. The journey from Sudan was so long and difficult, their mothers said, that they arrived with little. There was no milk for the children, no meat for themselves. A 9-month-old baby who arrived weighing barely 9 pounds died within two days.

"We're poor now," said Zahara Adam Ali, 25, who is living at a refugee camp in Darfur. "We had a house and we had enough to eat. The men on horses took everything."

Somini Sengupta is a Times correspondent based in Dakar, Senegal; additional reporting by Marc Lacey, The Times's bureau chief in Nairobi, Kenya.