Between 6,000 and 10,000 people are dying from disease and violence each month in Sudan's Darfur region as heavy rains and a marauding militia hinder U.N. efforts to respond to one of Africa's worst humanitarian crises, according to a survey of mortality rates by the United Nations' World Health Organization.

The latest U.N. figures demonstrate that survival rates have worsened in Darfur over the past three months as the United Nations struggles to provide food to nearly 1 million displaced people in more than 120 camps throughout Darfur. The main killers are preventable conditions such as diarrhea, which accounted for nearly a quarter of the deaths, and a wave of violence that has plagued the region since civil war began in February 2003.

Sudan challenged the findings of the survey, saying that mortality rates among displaced civilians in Darfur are improving. "I do not think this assessment is correct," Sudan's minister of humanitarian affairs, Ibrahim Mahmoud Hamid, told reporters in Khartoum after a meeting with Andrew S. Natsios, head of the U.S. Agency for International Development. "The death rate is decreasing."

The Bush administration has accused Sudan and a government-backed militia of committing genocide. The United States is pressing the U.N. Security Council to adopt a resolution this week threatening to consider oil industry sanctions against Khartoum if it does not crack down on the militia and invite thousands of additional African monitors into Darfur.

The resolution also calls for a formal U.N. inquiry into human rights abuses to determine if genocide has occurred there. The European Union backed the Bush administration's call for a U.N. commission of inquiry to determine whether the government or government- backed militia is guilty of committing genocide.

In an attempt to broaden support for the resolution, the United States presented council members on Tuesday with a revised version of the resolution. It softened the threat of sanctions, asking only that the council "shall consider" imposing punitive measures against Sudan if it fails to comply with its obligations. A previous version warned that the council "will take further actions" if Sudan does not comply.

"Our hope is that the vote will come towards the end of the week. But we feel that the time is of the essence," said John C. Danforth, the U.S. ambassador to the United Nations. "With respect to the number of people dying in Darfur, it is a very large number of people, and it is a true tragedy, and all the more urgent the need for getting the African Union in place, which is the most immediate thing that can be done to help the people of Darfur."

The United States and human rights groups allege that Sudan and an Arab militia known as Janjaweed have used extreme violence as part of a counterinsurgency campaign, killing tens of thousands of black African villagers in Darfur and driving more than 1 million from their homes.

The U.N. estimates represent the most extensive study of mortality rates in Darfur and are drawn from a survey by WHO and Sudanese government epidemiologists of more than 3,100 households between June 15 and Aug. 15. The figures are not nearly as high as the worst-case-scenario projections of USAID; it predicted that as many as 300,000 will die over nine months, including as many as 36,000 in August.

State Department spokesman Richard A. Boucher said: "Whatever the [precise] numbers are, I think we all understand it's a terrible situation, a situation where many, many people are suffering and many, many people remain at risk."

"These death rates indicate that there is a humanitarian crisis in these states," the WHO survey said. "The population, especially in the West and possibly in the North, is dying at between five and ten times the rate that is normal for people in Sudan."

U.N. officials cautioned that the results are preliminary and that death rates in the region could be higher. "Delivering relief to these communities is one of the most difficult tasks any of us have been involved in," said David Nabarro, head of WHO's action team. "We are still worried that we are underestimating mortality rates."